Добірка наукової літератури з теми "Annual refrigeration energy production"

It is justified the necessity of taking into consideration changes in thermal loads on the air conditioning system (heat and moisture treatment of air by cooling it with decreasing temperature and moisture content) in accordance with the current climatic conditions of operation. Since the effect of air cooling depends on the duration of its use and the amount of cold consumption, it is suggested that it be determined by the amount of cold spent per year for air conditioning at the GTU inlet, that is, for annual refrigerating capacity. The example of heat-using air conditioning at the inlet of a gas turbine unite (energy–efficient air conditioning systems) analyzes the annual costs of cooling for cooling ambient air to the temperature of 15 °C by an absorption lithium-bromide chiller and two-stage air cooling: to a temperature of 15 °C in an absorption lithium-bromide chiller and down to temperature 10 °С – in a refrigerant ejector chiller as the stages of a two-stage absorption-ejector chiller, depending on the installed (project) refrigerating capacity of waste heat recovery chiller.It is shown that, based on the varying rate of increment in the annual production of cold (annual refrigeration capacity) due to the change in the thermal load in accordance with current climatic conditions, it is necessary to select such a design thermal load for the air conditioning system (installed refrigeration capacity of chillers), which ensures the achievement of maximum or close to it annual production of cold at a relatively high rate of its increment. It is analyzed the dependence of the increment on the annual refrigerated capacity, relative to the installed refrigeration capacity, on the installed refrigeration capacity, in order to determine the installed refrigeration capacity, which provides the maximum rate of increase in the annual refrigerating capacity (annual production of cold). Based on the results of the research, it is proposed the method for determining the rational thermal load of the air conditioning system (installed – the design refrigeration capacity of the chiller) in accordance with the changing climatic conditions of operation during the year, which provides nearby the maximum annual production of cold at relatively high rates of its growth

Abstract The article considers ways to reduce energy costs in the cold using ozone-safe refrigerants production. In this case, it is necessary to include an air-cooled heat exchanger-pre-condenser in the technological scheme of refrigeration. The conditions for the pre-capacitor for a certain performance selection are formulated. The results of the presented calculations prove a decrease in the annual energy consumption for cold production in comparison with the technological scheme with external cooling and a cascade system. The energy consumption reducing principle of the installation due to the air pre-condenser can also be realized by installing a heat-exchanger on the discharge of low-temperature compressors to heat water for the enterprise needs, receiving free heat energy all year round.

Thermal systems of buildings in the tropics are highly energy intensive. In this study, a novel integrated solar photovoltaic–thermal–refrigeration (PVTR) system used to produce hot water and air-conditioning in the tropical climate conditions of Singapore was analyzed. A dynamic simulation model was formulated for the analysis. Mathematical models were developed for the PV sandwich attached with a solar flat plate collector and for the main components of the refrigeration system. Thorough investigation of the electrical and thermal performances of the system were conducted through the analysis of coefficient of performance (COP), cooling capacity, water temperature and heat capacity in water heater, photovoltaic (PV) module temperature and PV efficiency. The results show that attractive electrical and thermal performance can be achieved with a maximum annual cooling COP of 9.8 and a heating COP of 11.3. The PV efficiency and power saving were 14% and 53%, respectively. The annual cooling, heating and PV energy produced were 9.7, 15.6 and 1.6[Formula: see text]MWh, respectively. The financial payback period of the system was 3.2 years and greenhouse gas (GHG) emission reduction annually was 12.6 tons of CO2 equivalents (tCO2e).

Co-generation systems, together with absorption refrigeration and thermal storage, can result in substantial benefits from the economic, energy and environmental point of view. Optimization of operation of such systems is important as a component of the entire optimization process in pre-construction phases, but also for short-term energy production planning and system control. This paper proposes an approach for operational optimization of energy supply systems with small or medium scale co-generation, additional boilers and heat pumps, absorption and compression refrigeration, thermal energy storage and interconnection to the electric utility grid. In this case, the objective is to minimize annual costs related to the plant operation. The optimization problem is defined as mixed integer nonlinear and solved combining modern stochastic techniques: genetic algorithms and simulated annealing with linear programming using the object oriented ?ESO-MS? software solution for simulation and optimization of energy supply systems, developed as a part of this research. This approach is applied to optimize a hypothetical plant that might be used to supply a real residential settlement in Nis, Serbia. Results are compared to the ones obtained after transforming the problem to mixed 0-1 linear and applying the branch and bound method.

AbstractLarge-scale heat pumps (HPs) and refrigeration plants are essential technologies to decarbonise the heating and cooling sector. District heating and cooling (DHC) can be supplied with low carbon footprint, if power generated from renewable energy sources is used. The simultaneous supply of DHC is often not considered in energy planning, nor the characteristics of the heat source and sink. Simplified approaches may not reveal the true potential of HPs and chillers. In this paper, different heat sources and sinks and their characteristics were considered for the simultaneous supply of DHC based on large-scale HPs and refrigeration plants. An optimization model was developed based on mixed-integer linear programming. The model is able to identify ideal production and storage capacities, heat sources and sinks based on realistic hourly operation profiles. By doing so, it is possible to identify the most economical or sustainable supply of DHC using electricity. The optimization model was applied to the Nordhavn area, a new development district of Copenhagen, Denmark. The results show that a combination of different heat sources and sinks is ideal for the case study. A HP that uses the district cooling network as a heat source to supply DHC was shown to be very efficient and economical. Groundwater and sewage water HPs were proposed for an economical supply of district heating. The Pareto frontier showed that a large reduction in annual CO2 emissions is possible for a relatively small increase in investments.

Abstract Large-scale heat pumps (HPs) and refrigeration plants are essential technologies to decarbonise the heating and cooling sector. District heating and cooling (DHC) can be supplied with low carbon footprint, if power generated from renewable energy sources is used. The simultaneous supply of DHC is often not considered in energy planning, nor the characteristics of the heat source and sink. Simplified approaches may not reveal the true potential of HPs and chillers. In this paper, different heat sources and sinks and their characteristics were considered for the simultaneous supply of DHC based on large-scale HPs and refrigeration plants. An optimization model was developed based on mixed-integer linear programming. The model is able to identify ideal production and storage capacities, heat sources and sinks based on realistic hourly operation profiles. By doing so, it is possible to identify the most economical or sustainable supply of DHC using electricity. The optimization model was applied to the Nordhavn area, a new development district of Copenhagen, Denmark. The results show that a combination of different heat sources and sinks is ideal for the case study. A HP that uses the district cooling network as a heat source to supply DHC was shown to be very efficient and economical. Groundwater and sewage water HPs were proposed for an economical supply of district heating. The Pareto frontier showed that a large reduction in annual CO2 emissions is possible for a relatively small increase in investments.

Maintaining the operation of refrigeration compressors in nominal or close modes by selecting a rational design thermal load and distributing it in response to the behavior of the current thermal load according to the current climatic conditions is one of the promising reserves for improving the energy efficiency of air conditioning systems, which implementation ensures maximum or close to it in the annual cooling production according to air conditioning duties. In general case, the total range of current thermal loads of any air-conditioning system includes a range of unstable loads caused by precooling of ambient air with significant fluctuations in the cooling capacity according to current climatic conditions, and a range of relatively stable cooling capacity expended for further lowering the air temperature from a certain threshold temperature to the final outlet temperature. If a range of stable thermal load can be provided within operating a conventional compressor in a mode close to nominal, then precooling the ambient air with significant fluctuations in thermal load requires adjusting the cooling capacity by using a variable speed compressor or using the excess of heat accumulated at reduced load. Such a stage principle of cooling ensures the operation of refrigerating machines matching the behavior of current thermal loads of any air-conditioning system, whether the central air conditioning system with ambient air procession in the central air conditioner or its combination with the local indoors recirculation air conditioning systems in the air-conditioning system. in essence, as combinations of subsystems – precooling of ambient air with the regulation of cooling capacity and subsequent cooling air to the mouth of the set point temperature under relatively stable thermal load.

Renewable energies are often subject to stochastic resources and daily cycles. Energy storage systems are consequently applied to provide a solution for the mismatch between power production possibility and its utilization period. In this study, a solar integrated thermo-electric energy storage (S-TEES) is analyzed both from an economic and environmental point of view. The analyzed power plant with energy storage includes three main cycles, a supercritical CO2 power cycle, a heat pump and a refrigeration cycle, indirectly connected by sensible heat storages. The hot reservoir is pressurized water at 120/160 °C, while the cold reservoir is a mixture of water and ethylene glycol, maintained at −10/−20 °C. Additionally, the power cycle’s evaporator section rests on a solar-heated intermediate temperature (95/40 °C) heat reservoir. Exergo-economic and exergo-environmental analyses are performed to identify the most critical components of the system and to obtain the levelized cost of electricity (LCOE), as well as the environmental indicators of the system. Both economic and environmental analyses revealed that solar energy converting devices are burdened with the highest impact indicators. According to the results of exergo-economic analysis, it turned out that average annual LCOE of S-TEES can be more than two times higher than the regular electricity prices. However, the true features of the S-TEES system should be only fully assessed if the economic results are balanced with environmental analysis. Life cycle assessment (LCA) revealed that the proposed S-TEES system has about two times lower environmental impact than referential hydrogen storage systems compared in the study.

A variety of greenhouse gas reduction scenarios have been proposed around the world to ensure sustainable developments and strengthen the global response to the climate change. To cope with this, it is urgently needed to reduce the amount of energy used for the heating, ventilating, air conditioning, and refrigerating (HVAC&R) systems in large buildings. This study discusses the reduction of cooling energy in large office buildings through the minimization of changes in components and equipment, such as heat source equipment and pumps, changes in the layout and operating methods of chilled water circulation pumps, and changes in the temperatures of chilled and condenser water. To do this, this study targeted an entire cooling system consisting of a hydronic system, a chiller, and a cooling tower, and conducted a quantitative analysis of the energy consumption and of the reduction achieved through a change in the pumping system type in the cooling system and a change in the Korean standard design and temperature of chiller and cooling tower via EnergyPlus simulations. The simulation results showed a cooling energy reduction of 103.2 MWh/yr, around 15.7%, where the primary constant-speed system (Case A) was changed to a primary variable-speed pump (Case B) in the configuration with a chilled water circulation pump. To reduce the cooling energy further, annually 142.3 MWh, around 21.7%, Case C in this study changed the outlet temperature of the chiller and temperature difference from 7 °C, 5 K to 9 °C, 9 K. Finally, when applying a change in the condenser water production temperature from 32 to 23.9 °C in accordance with ASHRAE Standard 90.1 for Case D, a cooling energy saving of 182.4 MWh/yr was observed, which is about 27.8%.

Abstract The article presents the development of measures to ensure the required thermal condition and recommendations for support setting of underground mine workings in the conditions of the cryolithozone, ensuring the stability of the workings and safe living conditions in the galleries of the tourist complex “The Kingdom of permafrost” (TKoP), located on the 5th km of the Vilyuysky tract in Yakutsk. The following research methods were used: field observation of the temperature condition, visual inspection of the slope and underground mining of the tourist complex, the choice of a rational type of support setting, calculation of the parameters of the support, mathematical modeling and numerical calculations of the temperature condition. The main research results are obtained: the results of field observation of the thermal condition of underground mine workings of the tourist complex “The Kingdom of permafrost” in the winter and spring period of operation, the results of visual inspection of the slope, galleries and chambers, and recommendations for ensuring stability and support setting the existing fallout zones are given. The calculation of the temperature condition of the TKoP and the required capacity of refrigeration machines was performed using the Museum CVM software package developed in the Laboratory of Mining Thermophysics of the IGDS SB RAS. To reduce the energy consumption for the production of artificial cold in the summer, it is recommended to carry out annual autumn and spring cooling charges with artificial ventilation. The recommendations for support setting mine workings have been developed.

In this thesis I find a function for how Gross Annual Energy Production per square meter of rotor area depends on wind data from the MIUU Mesoscale Atmospheric Model. The result can be used in the early stages of the process of finding a suitable site for a new wind farm. The relationship is found by looking at 325 wind turbines in Sweden and calculating the GAEP/m2 and plotting it against the wind speed given by MIUU. The final function is given by a linear regression and is stated in the equation below: GAEP/m2 = -576.96 + 209.18*MIUU Wind farm producers will be able to get a estimate of the GAEP by using the equation and the easily available data from the MIUU-model and can then make a shortlist of possible locations for the new turbines.

Successful wind power projects start with a realistic representation of the surface, more specifically the surface roughness of the site. This thesis investigates the use of airborne laser scans to model the surface roughness around a new wind farm. Estimations are made to find out how forest management and tree growth affects roughness length and displacement height. Data from scans two years apart for a specific site is provided by the Swedish governmental land registration authority. Next, tree height and plant area index methods are applied and analyzed using MATLAB. The results shows a difference of roughness length between 10.34% and 36.21% during an eight year period. WindPRO/WAsP is used to import roughness lengths for four specific cases. Height contour lines and meteorological data is taken from a long term corrected MESO data set. The results indicate a reduction in uncertainty in annual energy production between 0.79% and 2.89% across four different cases. This effect becomes significantly larger (12.76%) when comparing with classical land cover maps. Further on, effects of turbulence intensity are simulated.Finally, the results of a survey, sent to three large forest land owners in Sweden, show there is an interest in adapting forest management plans in favor of wind energy production if benefits can be shared.

“Waste of resources is a mortal sin at IKEA.” – Ingvar Kamprad IKEA, as one of the biggest furniture companies in the world (Alänge, 2015), makes it interesting to have a look into their practices to gain a deeper insight by looking at how they work on a more sustainable and environmental friendlier world. Since Ingvar Kamprad, the founder of this company, mentioned sustainability from the earliest years, this work will provide an insight on how the sustainability annual reports of IKEA present their sustainability strategies to the reader every year. The researchers use the secondary analysis method to provide the theoretical framework and apply a case study to conduct the empirical data of the company IKEA. Since (Harte et al., 1991) pointed out that annual reports are an important source of environmental information. The database is in form of annual reports from the year 2010 till 2018 that were provided by the company IKEA itself. Through the pattern matching method the numbers over the years are compared and discussed due to their development. Furthermore, the areas “production” and “supplier” are selected from the supply chain management and also included in the analyzes section, since both, the development of other organizational relationships in the supply chain and the environmental corporation can become an integral part of the company (Seuring & Müller, 2008). Through diagrams in the empirical chapter this work will provide a comparison between the different factors in the mentioned areas of the supply chain management and discuss the actual development and partly improvements of the factor’s “energy”, “waste”, “production” etc. and the promises and goals from the IKEA’s side.

This thesis introduces a design optimization methodology that is based on minimizing the Cost of Energy (COE) of a Horizontal Axis Wind Turbine (HAWT) that is to be operated at a specific wind site. In the design methodology for the calculation of the Cost of Energy, the Annual Energy Production (AEP) model to calculate the total energy generated by a unit wind turbine throughout a year and the total cost of that turbine are used. The AEP is calculated using the Blade Element Momentum (BEM) theory for wind turbine power and the Weibull distribution for the wind speed characteristics of selected wind sites. For the blade profile sections, either the S809 airfoil profile for all spanwise locations is used or NREL S-series airfoil families, which have different airfoil profiles for different spanwise sections, are used,. Lift and drag coefficients of these airfoils are obtained by performing computational fluid dynamics analyses. In sample design optimization studies, three different wind sites that have different wind speed characteristics are selected. Three scenarios are generated to present the effect of the airfoil shape as well as the turbine power. For each scenario, design optimizations of the reference wind turbines for the selected wind sites are performed the Cost of Energy and Annual Energy Production values are compared.

The recent worldwide economic crisis, climate change and global warming have emphasized that the need for low carbon emissions while also ensuring the economic feasibility. In this paper, wind power potential of ETD in KTH was investigated. The technical and economical feasibility of tower mounted small scale standalone wind turbine installation is conducted. The potential of wind power production was statistically analysed. The average wind speed data of four-season interval of one year period (2011) which its measurement was taken on the roof top of the ETDB, and this was adopted and analysed in order to find out the potential of wind power generation. The Rayleigh distribution probability was applied to calculate the wind speed distribution at KTH, by doing so the annual wind power potential at the area and annual energy production of the chosen wind turbine was estimated, after the selection of a proper wind turbine have been made upon the site conditions. Therefore, the study result shows that installation of the wind turbine at 24 meters hub height for this particular area will have a better performance of annual energy production, capacity factor, carbon savings and better economical value than the current turbine installed at 17 meters height at the ETD. The economic evaluation shows that the turbine can save an electricity bill of US$3661.05 per year and cover 1.84% of the electricity consumption of the ETD by reducing its respective CO2 emission from the electricity use at the department. Moreover, the payback period of the turbine installation with the inclusion of the green certificate is approximately 14 years which is more feasible if it is considered for small wind turbines too, which is already in practice for renewables including wind power in Sweden.

Le développement de la production d'énergie éolienne nécessite des méthodes précises et bien établies pour l'évaluation de la ressource éolienne, étape essentielle dans la phase avant-projet d'une future ferme. Au cours de ces deux dernières décennies, les modèles d'écoulements linéaires ont été largement utilisés dans l'industrie éolienne pour l'évaluation de la ressource et pour la définition de la disposition des turbines. Cependant, les incertitudes des modèles linéaires dans la prévision de la vitesse du vent sur terrain complexe sont bien connues. Elles conduisent à l'utilisation de modèles CFD, capables de modéliser les écoulements complexes de manière précise autour de caractéristiques géographiques spécifiques. Les modèles méso-échelle peuvent prédire le régime de vent à des résolutions de plusieurs kilomètres mais ne sont pas bien adaptés pour résoudre les échelles spatiales inférieures à quelques centaines de mètres. Les modèles de CFD peuvent capter les détails des écoulements atmosphériques à plus petite échelle, mais nécessitent de documenter précisément les conditions aux limites. Ainsi, le couplage entre un modèle méso-échelle et un modèle CFD doit permettre d'améliorer la modélisation fine de l'écoulement pour les applications dans le domaine de l'énergie éolienne en comparaison avec les approches opérationnelles actuelles. Une campagne de mesure d'un an a été réalisée sur un terrain complexe dans le sud de la France durant la période 2007-2008. Elle a permis de fournir une base de données bien documentée à la fois pour les paramètres d'entrée et les données de validation. La nouvelle méthodologie proposée vise notamment à répondre à deux problématiques: le couplage entre le modèle méso-échelle et le modèle CFD en prenant en compte une forte variation spatiale de la topographie sur les bords du domaine de simulation, et les erreurs de prédiction du modèle méso-échelle. Le travail réalisé ici a consisté à optimiser le calcul du vent sur chaque face d'entrée du modèle CFD à partir des valeurs issues des verticales du modèle de méso-échelle, puis à mettre en œuvre une assimilation de données basée sur la relaxation newtonienne (nudging). La chaîne de modèles considérée ici est composée du modèle de prévision de Météo-France ALADIN et du code de CFD open-source Code_Saturne. Le potentiel éolien est ensuite calculé en utilisant une méthode de clustering, permettant de regrouper les conditions météorologiques similaires et ainsi réduire le nombre de simulations CFD nécessaires pour reproduire un an (ou plus) d'écoulement atmosphérique sur le site considéré. La procédure d'assimilation est réalisée avec des mesures issues d'anémomètre à coupelles ou soniques. Une analyse détaillée des simulations avec imbrication et avec ou sans assimilation de données est d'abord présentée pour les deux directions de vent dominantes, avec en particulier une étude de sensibilité aux paramètres intervenant dans l'imbrication et dans l'assimilation. La dernière partie du travail est consacrée au calcul du potentiel éolien en utilisant une méthode de clustering. La vitesse annuelle moyenne du vent est calculée avec et sans assimilation, puis est comparée avec les mesures non assimilées et les résultats du modèle WAsP. L'amélioration apportée par l'assimilation de données sur la distribution des écarts avec les mesures est ainsi quantifiée pour différentes configurations
The development of wind energy generation requires precise and well-established methods for wind resource assessment, which is the initial step in every wind farm project. During the last two decades linear flow models were widely used in the wind industry for wind resource assessment and micro-siting. But the linear models inaccuracies in predicting the wind speeds in very complex terrain are well known and led to use of CFD, capable of modeling the complex flow in details around specific geographic features. Mesoscale models (NWP) are able to predict the wind regime at resolutions of several kilometers, but are not well suited to resolve the wind speed and turbulence induced by the topography features on the scale of a few hundred meters. CFD has proven successful in capturing flow details at smaller scales, but needs an accurate specification of the inlet conditions. Thus coupling NWP and CFD models is a better modeling approach for wind energy applications. A one-year field measurement campaign carried out in a complex terrain in southern France during 2007-2008 provides a well documented data set both for input and validation data. The proposed new methodology aims to address two problems: the high spatial variation of the topography on the domain lateral boundaries, and the prediction errors of the mesoscale model. It is applied in this work using the open source CFD code Code_Saturne, coupled with the mesoscale forecast model of Météo-France (ALADIN). The improvement is obtained by combining the mesoscale data as inlet condition and field measurement data assimilation into the CFD model. Newtonian relaxation (nudging) data assimilation technique is used to incorporate the measurement data into the CFD simulations. The methodology to reconstruct long term averages uses a clustering process to group the similar meteorological conditions and to reduce the number of CFD simulations needed to reproduce 1 year of atmospheric flow over the site. The assimilation procedure is carried out with either sonic or cup anemometers measurements. First a detailed analysis of the results obtained with the mesoscale-CFD coupling and with or without data assimilation is shown for two main wind directions, including a sensitivity study to the parameters involved in the coupling and in the nudging. The last part of the work is devoted to the estimate of the wind potential using clustering. A comparison of the annual mean wind speed with measurements that do not enter the assimilation process and with the WAsP model is presented. The improvement provided by the data assimilation on the distribution of differences with measurements is shown on the wind speed and direction for different configurations

The aim of this thesis is to evaluate different repowering alternatives from the viewpoint of increasing power production from existing offshore wind farms (OWF), as some of the first commissioned OWFs are approaching the end of their expected lifetime. The thesis presents a literature review of components and financial aspects that are of importance for repowering of OWFs. In the literature review, risks and uncertainties regarding repowering are also lifted and analysed. The thesis contains a case study on Horns Rev 1 OWF, where three different repowering scenarios are evaluated by technical and financial performance, aiming to compare the cost of repowering alternatives. The design of the case study is based around previous studies of offshore repowering having focused mainly on achieving the lowest possible levelized cost of energy (LCoE) and highest possible capacity factor, often resulting in suggested repowering utilizing smaller wind turbines than the existing ones. In order to evaluate the financial viability of repowering alternatives, the software RETScreen Expert was used to estimate the annual energy production (AEP) after losses and calculate the net present value (NPV) and LCoE for lifetime extension and full repowering utilizing different capacity wind turbines. Input values from the literature as well as real wind resource measurements from the site was utilized to achieve as accurate results as possible. The result of the case study shows that repowering of OWFs have the possibility of providing a very strong business case with all scenarios resulting in a positive NPV as well as lower LCoE than the benchmarked electricity production price. Although the initial investment cost of the different repowering alternatives presented in this thesis still are uncertain to some extent, due to the lack of reliable costs for repowering alternatives, this thesis provides a base for further research regarding the repowering of OWFs.

The wind power prediction plays a vital role in a wind power project both during the planning and operational phase of a project. A time series based wind power prediction model is introduced and the simulations are run for different case studies. The prediction model works based on the input from 1) nearby representative wind measuring station 2) Global average wind speed value from Meteorological Institute Uppsala University mesoscale model (MIUU) 3) Power curve of the wind turbine. The measured wind data is normalized to minimize the variation in the wind speed and multiplied with the MIUU to get a distributed wind speed. The distributed wind speed is then used to interpolate the wind power with the help of the power curve of the wind turbine. The interpolated wind power is then compared with the Actual Production Data (APD) to validate the prediction model. The simulation results show that the model works fairly predicting the Annual Energy Production (AEP) on monthly averages for all sites but the model could not follow the APD trend on all cases. The sensitivity analysis shows that the variation in production does not depend on ’the variation in roughness class’ nor ’the difference in distance between the measuring station and the wind farm’. The thesis has been concluded from the results that the model works fairly predicting the AEP for all cases within the variation bounds. The accuracy of the model has been validated only for monthly averages since the APD was available only on monthly averages. But the accuracy could be increased based on future work, to assess the Power law exponent (a) parameter for different terrain and validate the model for different time scales provided if the APD is available on different time scales.

The efficiency of refrigeration capacity regulation in ambient air conditioning systems = Ефективність регулювання холодопродуктивності в системах кондиціювання зовнішнього повітря / E. Trushliakov, A. Radchenko, M. Radchenko, S. Kantor, O. Zielikov // Матеріали XI міжнар. наук.-техн. конф. "Інновації в суднобудуванні та океанотехніці". В 2 т. – Миколаїв : НУК, 2020. – Т. 1. – С. 475–480.
Розроблено новий метод і підхід до аналізу ефективності системи кондиціювання зовнішнього повітря, згідно з яким весь діапазон змінних теплових навантажень поділяється на дві зони: зона обробки навколишнього повітря зі значними коливаннями поточного теплового навантаження і зона без коливань. Пропонований спосіб регулювання холодопродуктивності дозволяє підвищити ефективність використання встановленої холодопродуктивності в поточних кліматичних умовах.
Abstract. A new method and approach to analyzing the efficiency of ambient air conditioning system has been developed, according to which the overall range of changeable heat loads is divided in two zones: the zone of ambient air processing with considerable fluctuations of the current heat load and a zone without fluctuations. The proposed method of the refrigeration capacity regulation allows to increase the efficiency of utilizing the installed refrigeration capacity in current climatic conditions.

The monograph examines the problems of sustainable development and energy efficiency using the scientific and methodological approach proposed by the authors for the development of regional fuel and energy programs based on the KhMAO, the Sverdlovsk region, and the oil and gas production enterprise JSC Yuganskneftegaz, and presents the results of the environmental and economic assessment. This approach allows us to evaluate and select the most effective investment project for the utilization of associated petroleum gas from the point of view of energy, environmental and climate security on comparable indicators (tons, rubles). The authors proposed to distinguish from more than 200 UN indicators four basic indicators: the change in the green area (country, region, city, household) for the year; the level of energy efficiency; the amount of pollutants released per year; the annual amount of greenhouse gas emissions. It is proposed to consider the possibility of using the" energy " ruble of S. A. Podolinsky (kW / h) as a possible world reserve currency. Taking into account the unique experience of the region's participation in various projects of sustainable development, energy-efficient and low-carbon economy, it is proposed to create a market for waste and greenhouse gas emissions on the basis of the trade exchange of the Sverdlovsk region as a pilot platform for the implementation of the green economy. The history of the term "green economy", the essence of this concept is considered; the results of the application of green economy in different countries are shown. The international experience of green solutions and technologies is analyzed, the psychological aspects of the transition to a green economy are studied. For all those interested in the environmental development of the economy.

AbstractThe chapter aims to explore the determinants of electricity consumption in working-class districts of Senegal cities. Grand-Yoff and Grand-Dakar are among the 19 district municipalities of the city of Dakar. The study collected data on different parameters related to electricity consumption that includes the number and type of plugging appliances. The methodology consists of a comparison between real electricity consumption of residential buildings and estimations based on models from the literature, which is followed by an analysis of the impact that a number of socio-economic parameters can have on the annual electricity consumption. Our results show that estimations can significantly differ from data collected in the field. They also show that context-specific, social and economic parameters affect electricity consumption in various magnitudes. Therefore, the planning of electricity production systems such as community grids or other decentralized systems for these areas requires better models.

The emerging Distributed Energy Resources (DER) program envisions extensive use of small to midsize turbines for on-site power production. Their output decreases substantially at warm ambient conditions when it is most needed. Therefore inlet air cooling had received much scrutiny as a way to avoid this degradation. This study examines three approaches to inlet air cooling: evaporative cooling; mechanical vapor compression refrigeration; and waste heat powered absorption refrigeration. The benefits and limitations of each process were documented. Ammonia absorption refrigeration is shown to deliver the greatest benefit to continuosly operating turbines at very favorable installed and operating cost. The most economical process identified included an ammonia refrigeration cycle integrated directly into the combustion turbine cycle. This cycle was designed and modeled, and analyzed with ambient temperature conditions for six geographic areas (Boston, Atlanta, Los Angeles, Honolulu, Phoenix, and Chicago). Annual benefits for each area are detailed.

Excess natural gas produced in oilfields is routinely flared due to the absence of alternative uses. Similarly, landfills emit large quantities of methane, which is primarily flared or vented. Both these activities result in large scale energy waste and undesired methane and carbon dioxide emissions. This work examines the benefits of using excess natural gas to harvest atmospheric moisture. Natural gas-powered refrigeration systems can enable large scale dehumidification via condensation. The harvested water can be used for water-intensive operations like hydraulic fracturing, drilling and waterflooding in nearby oilfields. This solution thus addresses the issues of energy waste, water and greenhouse gas emissions A first-order model is used to estimate the water harvest, based on the gas flow rate, ambient weather and the refrigeration system. The benefits of flared gas-powered water harvesting are quantified for the Eagle Ford (Texas) and the Bakken (North Dakota) Shales, which account for the bulk of US flaring. The benefits of landfill gas-powered water harvesting are quantified for the Barnett (Texas), and Monterey (California) Shales, which can be served by 30 and 15 landfills, respectively. Overall, flared gas utilization for water production can meet 15% and 60% of the annual water requirements of the Eagle Ford and Bakken Shales, respectively. The water harvested using landfill gas (from nearby landfills) can meet 22% and 73% of the annual water requirements of the Barnett and Monterey Shales, respectively. This technology will also eliminate millions of trucking trips to transport water. Overall, this waste-to-value concept has global relevance, since a combination of excess gas availability, water scarcity and hot-humid conditions is common in many regions of the world.

Thermal characteristics of energy efficient buildings are analyzed and energy demands are estimated. A concept of combined compressor – ejector thermal system for simultaneous production of electricity, heating, refrigeration and air conditioning is exposed. The performance characteristics of the natural gas prime motor – electric generator are assessed and optimum construction of the combined compressor – ejector refrigeration / heat pump unit is proposed to satisfy the energy demands for electricity, heating, cooling and air conditioning. Basic thermal calculations, material and energy balances of the complete thermal system are carried out and optimizing procedures for the thermal system components are given. A comparison of the proposed thermal systems and energy (natural gas) consumption with the conventional thermal systems and energy consumption for electricity, heating (natural gas - boiler), cooling (electricity – compressor refrigeration system) and air conditioning is made.

Thermal characteristics of energy efficient buildings are analyzed and energy demands are estimated. A concept of combined compressor – ejector thermal system for simultaneous production of electricity, heating, refrigeration and air conditioning is exposed. The performance characteristics of the natural gas prime motor – electric generator are assessed and optimum construction of the combined compressor – ejector refrigeration / heat pump unit is proposed to satisfy the energy demands for electricity, heating, cooling and air conditioning. Basic thermal calculations, material and energy balances of the complete thermal system are carried out and optimizing procedures for the thermal system components are given. A comparison of the proposed thermal systems and energy (natural gas) consumption with the conventional thermal systems and energy consumption for electricity, heating (natural gas - boiler), cooling (electricity – compressor refrigeration system) and air conditioning is made.

Many industries have significant requirements regarding temperature control, air humidity and air pollution which must be strictly adhered to avoid bacterial formation and contamination. High refrigeration specifications are only required in certain areas. However, these specifications are often applied across the whole production hall which results in unnecessarily high energy demand and usage. A more energy efficient approach is the localized cooling of the product, which conditions the direct environment of the product only. This leads to the consideration of separating or localizing the products specifically requiring refrigeration in the production hall. In this paper, localized product cooling systems are analyzed in order to identify the savings potential associated with a localized refrigeration system. The study shows the energy savings potential for a manufacturing company located in three different locations: in Germany, Canada and the USA.

The current electrical refrigeration and air condition systems are considered as one of the major sources for ozone depletion and global warming problems. Furthermore, they consume a large percentage of the worldwide gross production of electricity (around 17%). Therefore, developing new refrigeration systems that might be able to work using renewable sources (solar, geothermal, etc.) and waste heat sources is necessary to address these problems. In this paper, the experimental investigation of an innovative thermal-mechanical refrigeration (TMR) system is presented. The TMR system replaces the electric compressor of the conventional refrigeration systems with an innovative expander-compressor unit (two connected double-acting cylinders). The proposed ECU can be driven by ultra-low heat temperature sources, has simple configuration, and high flexibility for the operating conditions. A hybrid electric-compressor and ECU refrigeration setup was developed to investigate the performance of the ECU and compare it to that of an electric compressor. The experiment was conducted using R134a as a working fluid at different masses. The results show that a maximum COP of 0.57 is obtained at a refrigerant mass of 30g (in electric mode) and a maximum COP of 0.41 is obtained at a refrigerant mass of 60g (in ECU mode).

• Energy transition in the transportation sector is indicated by the gradual shifting from the use of internal combustion engine (ICE) vehicles to electric vehicles (EVs) globally. • The transportation sector consumed 43% of total global energy and emitted 16.2% of total global emissions in 2020. Similarly, the transportation sector in Indonesia consumed 45% of the total energy and contributed to 13.6% of CO2 emission in 2019. • Global EV development and utilization are increasing exponentially, especially in developed countries, and there were 10 million EVs in 2020 worldwide. • China has successfully dominated global EVs, both in EV utilization and manufacturing with 45% global EVs Stock and 77% global EV batteries production. • Geopolitically, the abundance of Indonesian nickel reserves provides Indonesia a great opportunity to be one of the main players in EV battery manufacturing. • With an annual average growth of 6%, the projected motorized vehicles growth in Indonesia will reach 214 million in 2030. The right government policies would make Indonesia become the Southeast Asia EV market hub as Indonesia has the largest automotive sales and production market among ASEAN countries. • Measurable and realistic national EV development targets and plans supported by executing policies such as fiscal incentives and hardware standardization, sufficient EV charging infrastructure, and other supporting infrastructures are key elements that drive successful EV development in several countries. • Insufficient domestic industries and technology, and the absence of policies that comprehensively cover the customers and producers directly to support EV development and utilization in Indonesia, resulting in the achieved number of EVs and EV infrastructures in Indonesia are far from the updated target or even the initial target (RUEN, 2017).

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.

Macroeconomic summary The Colombian economy sustained numerous shocks in the second quarter, pri¬marily related to costs and supply. The majority of these shocks were unantic¬ipated or proved more persistent than expected, interrupting the recovery in economic activity observed at the beginning of the year and pushing overall inflation above the target. Core inflation (excluding food and regulated items) increased but remained low, in line with the technical staff’s expectations. A third wave of the pandemic, which became more severe and prolonged than the previous outbreak, began in early April. This had both a high cost in terms of human life and a negative impact on Colombia's economic recovery. Between May and mid-June roadblocks and other disruptions to public order had a sig¬nificant negative effect on economic activity and inflation. The combination and magnitude of these two shocks likely led to a decline in gross domestic product (GDP) compared to the first quarter. Roadblocks also led to a significant in¬crease in food prices. The accumulated effects of global disruptions to certain value chains and increased international freight transportation prices, which since the end of 2020 have restricted supply and increased costs, also affected Colombia’s economy. The factors described above, which primarily affected the consumer price index (CPI) for goods and foods, explain to a significant degree the technical staff’s forecast errors and the increase in overall inflation above the 3% target. By contrast, increases in core inflation and in prices for regulated items were in line with the technical staff’s expectations, and can be explained largely by the elimination of various price relief measures put in place last year. An increase in perceived sovereign risk and the upward pressures that this im¬plies on international financing costs and the exchange rate were further con¬siderations. Despite significant negative shocks, economic growth in the first half of the year (9.1%) is now expected to be significantly higher than projected in the April re¬port (7.1%), a sign of a more dynamic economy that could recover more quickly than previously forecast. Diverse economic activity figures have indicated high¬er-than-expected growth since the end of 2020. This suggests that the negative effects on output from recurring waves of COVID-19 have grown weaker and less long-lasting with subsequent outbreaks. Nevertheless, the third wave of the coro¬navirus, and to an even greater degree the previously mentioned roadblocks and disruptions to public order, likely led to a decline in GDP in the second quar¬ter compared to the first. Despite this, data from the monthly economic tracking indicator (ISE) for April and May surpassed expectations, and new sector-level measures of economic activity suggest that the negative impact of the pandemic on output continues to moderate, amid reduced restrictions on mobility and im¬provements in the pace of vaccination programs. Freight transportation registers (June) and unregulated energy demand (July), among other indicators, suggest a significant recovery following the roadblocks in May. Given the above, annual GDP growth in the second quarter is expected to have been around 17.3% (previously 15.8%), explained in large part by a low basis of comparison. The technical staff revised its growth projection for 2021 upward from 6% to 7.5%. This forecast, which comes with an unusually high degree of uncertain¬ty, assumes no additional disruptions to public order and that any new waves of COVID-19 will not have significant additional negative effects on economic activity. Recovery in international demand, price levels for some of Colombia’s export com¬modities, and remittances from workers abroad have all performed better than projected in the previous report. This dynamic is expected to continue to drive recovery in the national income over the rest of the year. Continued ample international liquidity, an acceleration in vacci¬nation programs, and low interest rates can also be ex¬pected to favor economic activity. Improved performance in the second quarter, which led to an upward growth revision for all components of spending, is expected to continue, with the economy returning to 2019 production levels at the end of 2021, earlier than estimated in the April report. This forecast continues to account for the short-term effects on aggregate demand of a tax reform package along the lines of what is currently being pro-posed by the national government. Given the above, the central forecast scenario in this report projects growth in 2021 of 7.5% and in 2022 of 3.1% (Graph 1.1). In this scenar¬io, economic activity would nonetheless remain below potential. The noted improvement in these projections comes with a high degree of uncertainty. Annual inflation increased more than expected in June (3.63%) as a result of changes in food prices, while growth in core inflation (1.87%) was similar to projections.

Macroeconomic summary Several factors contributed to an increase in projected inflation on the forecast horizon, keeping it above the target rate. These included inflation in December that surpassed expectations (5.62%), indexation to higher inflation rates for various baskets in the consumer price index (CPI), a significant real increase in the legal minimum wage, persistent external and domestic inflationary supply shocks, and heightened exchange rate pressures. The CPI for foods was affected by the persistence of external and domestic supply shocks and was the most significant contributor to unexpectedly high inflation in the fourth quarter. Price adjustments for fuels and certain utilities can explain the acceleration in inflation for regulated items, which was more significant than anticipated. Prices in the CPI for goods excluding food and regulated items also rose more than expected. This was partly due to a smaller effect on prices from the national government’s VAT-free day than anticipated by the technical staff and more persistent external pressures, including via peso depreciation. By contrast, the CPI for services excluding food and regulated items accelerated less than expected, partly reflecting strong competition in the communications sector. This was the only major CPI basket for which prices increased below the target inflation rate. The technical staff revised its inflation forecast upward in response to certain external shocks (prices, costs, and depreciation) and domestic shocks (e.g., on meat products) that were stronger and more persistent than anticipated in the previous report. Observed inflation and a real increase in the legal minimum wage also exceeded expectations, which would boost inflation by affecting price indexation, labor costs, and inflation expectations. The technical staff now expects year-end headline inflation of 4.3% in 2022 and 3.4% in 2023; core inflation is projected to be 4.5% and 3.6%, respectively. These forecasts consider the lapse of certain price relief measures associated with the COVID-19 health emergency, which would contribute to temporarily keeping inflation above the target on the forecast horizon. It is important to note that these estimates continue to contain a significant degree of uncertainty, mainly related to the development of external and domestic supply shocks and their ultimate effects on prices. Other contributing factors include high price volatility and measurement uncertainty related to the extension of Colombia’s health emergency and tax relief measures (such as the VAT-free days) associated with the Social Investment Law (Ley de Inversión Social). The as-yet uncertain magnitude of the effects of a recent real increase in the legal minimum wage (that was high by historical standards) and high observed and expected inflation, are additional factors weighing on the overall uncertainty of the estimates in this report. The size of excess productive capacity remaining in the economy and the degree to which it is closing are also uncertain, as the evolution of the pandemic continues to represent a significant forecast risk. margin, could be less dynamic than expected. And the normalization of monetary policy in the United States could come more quickly than projected in this report, which could negatively affect international financing costs. Finally, there remains a significant degree of uncertainty related to the duration of supply chocks and the degree to which macroeconomic and political conditions could negatively affect the recovery in investment. The technical staff revised its GDP growth projection for 2022 from 4.7% to 4.3% (Graph 1.3). This revision accounts for the likelihood that a larger portion of the recent positive dynamic in private consumption would be transitory than previously expected. This estimate also contemplates less dynamic investment behavior than forecast in the previous report amid less favorable financial conditions and a highly uncertain investment environment. Third-quarter GDP growth (12.9%), which was similar to projections from the October report, and the fourth-quarter growth forecast (8.7%) reflect a positive consumption trend, which has been revised upward. This dynamic has been driven by both public and private spending. Investment growth, meanwhile, has been weaker than forecast. Available fourth-quarter data suggest that consumption spending for the period would have exceeded estimates from October, thanks to three consecutive months that included VAT-free days, a relatively low COVID-19 caseload, and mobility indicators similar to their pre-pandemic levels. By contrast, the most recently available figures on new housing developments and machinery and equipment imports suggest that investment, while continuing to rise, is growing at a slower rate than anticipated in the previous report. The trade deficit is expected to have widened, as imports would have grown at a high level and outpaced exports. Given the above, the technical staff now expects fourth-quarter economic growth of 8.7%, with overall growth for 2021 of 9.9%. Several factors should continue to contribute to output recovery in 2022, though some of these may be less significant than previously forecast. International financial conditions are expected to be less favorable, though external demand should continue to recover and terms of trade continue to increase amid higher projected oil prices. Lower unemployment rates and subsequent positive effects on household income, despite increased inflation, would also boost output recovery, as would progress in the national vaccination campaign. The technical staff expects that the conditions that have favored recent high levels of consumption would be, in large part, transitory. Consumption spending is expected to grow at a slower rate in 2022. Gross fixed capital formation (GFCF) would continue to recover, approaching its pre-pandemic level, though at a slower rate than anticipated in the previous report. This would be due to lower observed GFCF levels and the potential impact of political and fiscal uncertainty. Meanwhile, the policy interest rate would be less expansionary as the process of monetary policy normalization continues. Given the above, growth in 2022 is forecast to decelerate to 4.3% (previously 4.7%). In 2023, that figure (3.1%) is projected to converge to levels closer to the potential growth rate. In this case, excess productive capacity would be expected to tighten at a similar rate as projected in the previous report. The trade deficit would tighten more than previously projected on the forecast horizon, due to expectations of an improved export dynamic and moderation in imports. The growth forecast for 2022 considers a low basis of comparison from the first half of 2021. However, there remain significant downside risks to this forecast. The current projection does not, for example, account for any additional effects on economic activity resulting from further waves of COVID-19. High private consumption levels, which have already surpassed pre-pandemic levels by a large margin, could be less dynamic than expected. And the normalization of monetary policy in the United States could come more quickly than projected in this report, which could negatively affect international financing costs. Finally, there remains a significant degree of uncertainty related to the duration of supply chocks and the degree to which macroeconomic and political conditions could negatively affect the recovery in investment. External demand for Colombian goods and services should continue to recover amid significant global inflation pressures, high oil prices, and less favorable international financial conditions than those estimated in October. Economic activity among Colombia’s major trade partners recovered in 2021 amid countries reopening and ample international liquidity. However, that growth has been somewhat restricted by global supply chain disruptions and new outbreaks of COVID-19. The technical staff has revised its growth forecast for Colombia’s main trade partners from 6.3% to 6.9% for 2021, and from 3.4% to 3.3% for 2022; trade partner economies are expected to grow 2.6% in 2023. Colombia’s annual terms of trade increased in 2021, largely on higher oil, coffee, and coal prices. This improvement came despite increased prices for goods and services imports. The expected oil price trajectory has been revised upward, partly to supply restrictions and lagging investment in the sector that would offset reduced growth forecasts in some major economies. Elevated freight and raw materials costs and supply chain disruptions continue to affect global goods production, and have led to increases in global prices. Coupled with the recovery in global demand, this has put upward pressure on external inflation. Several emerging market economies have continued to normalize monetary policy in this context. Meanwhile, in the United States, the Federal Reserve has anticipated an end to its asset buying program. U.S. inflation in December (7.0%) was again surprisingly high and market average inflation forecasts for 2022 have increased. The Fed is expected to increase its policy rate during the first quarter of 2022, with quarterly increases anticipated over the rest of the year. For its part, Colombia’s sovereign risk premium has increased and is forecast to remain on a higher path, to levels above the 15-year-average, on the forecast horizon. This would be partly due to the effects of a less expansionary monetary policy in the United States and the accumulation of macroeconomic imbalances in Colombia. Given the above, international financial conditions are projected to be less favorable than anticipated in the October report. The increase in Colombia’s external financing costs could be more significant if upward pressures on inflation in the United States persist and monetary policy is normalized more quickly than contemplated in this report. As detailed in Section 2.3, uncertainty surrounding international financial conditions continues to be unusually high. Along with other considerations, recent concerns over the potential effects of new COVID-19 variants, the persistence of global supply chain disruptions, energy crises in certain countries, growing geopolitical tensions, and a more significant deceleration in China are all factors underlying this uncertainty. The changing macroeconomic environment toward greater inflation and unanchoring risks on inflation expectations imply a reduction in the space available for monetary policy stimulus. Recovery in domestic demand and a reduction in excess productive capacity have come in line with the technical staff’s expectations from the October report. Some upside risks to inflation have materialized, while medium-term inflation expectations have increased and are above the 3% target. Monetary policy remains expansionary. Significant global inflationary pressures and the unexpected increase in the CPI in December point to more persistent effects from recent supply shocks. Core inflation is trending upward, but remains below the 3% target. Headline and core inflation projections have increased on the forecast horizon and are above the target rate through the end of 2023. Meanwhile, the expected dynamism of domestic demand would be in line with low levels of excess productive capacity. An accumulation of macroeconomic imbalances in Colombia and the increased likelihood of a faster normalization of monetary policy in the United States would put upward pressure on sovereign risk perceptions in a more persistent manner, with implications for the exchange rate and the natural rate of interest. Persistent disruptions to international supply chains, a high real increase in the legal minimum wage, and the indexation of various baskets in the CPI to higher inflation rates could affect price expectations and push inflation above the target more persistently. These factors suggest that the space to maintain monetary stimulus has continued to diminish, though monetary policy remains expansionary. 1.2 Monetary policy decision Banco de la República’s board of directors (BDBR) in its meetings in December 2021 and January 2022 voted to continue normalizing monetary policy. The BDBR voted by a majority in these two meetings to increase the benchmark interest rate by 50 and 100 basis points, respectively, bringing the policy rate to 4.0%.