Total Final Energy Consumption Research Articles

The Relationship of Causal Factors Affecting the Future Equilibrium Change of Total Final Energy Consumption in Thailand’s Construction Sector under a Sustainable Development Goal: Enriching the SE-VARX Model

This study aims to analyze the influence of the relationship between causal factors that affect the future equilibrium of the total final energy consumption in the construction sector of Thailand under the sustainable development policy for the period of 10 years (2019–2028). This analysis was achieved with the application of the Structure Equilibrium-Vector Autoregressive with Exogenous Variables model (SE-VARX model). This model was developed to fill research gaps and differs from those of previous studies. In the selection of variables, the study focused on Sustainable Development (SD)-based variables available through the lens of Thailand. The exogenous variables included real GDP, population growth, urbanization rate, industrial structure, oil price, foreign direct investment, international tourist arrivals, and total exports and imports. Every variable had a co-integration at level (1) and was used to structure the SE-VARX model. This particular model can effectively analyze the influence of the direct relationship and meet the criteria of goodness of fit without spuriousness. This SE-VARX model allowed us to discover that every variable in the model had an influence on the equilibrium change, where the real GDP is the fastest variable to adjust to the equilibrium while the total final energy consumption has the slowest adjustment ability. The SE-VARX model can be used to project the total final energy consumption, as verified by the performance test result. The test was measured based on the Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE), and their results were 1.09% and 1.01%, respectively. This performance result had the highest value compared to other models in the past. Thus, the SE-VARX model is suitable for forecasting over the next 10 years (2019–2038). The results of this study reveal that the total final energy consumption in the construction sector of Thailand will exhibit a continuously increasing growth rate from 2019 to 2028, amounting to about 144.29% or equivalent to 364.01 ktoe. In addition, the study also found that future government plans may be difficult to achieve as planned. Therefore, the introduced model should be integrated into national development planning and strategies to achieve sustainable development in the future and to enable its application to other sectors.

ENVIRONMENTAL CONCERNS OF ENERGY CHAIN AS A REFLECTION OF SUSTAINABILITY

Environmental policy integration (EPI) relates to the inclusion of environmental concerns in sectoral policies outside the conventional environmental policy domain. EPI has became a main concept in global environmental governance with the intention to link the incompatible objectives of economic competitiveness, social development and environmental protection with the concept of Sustainable Development (SD). Having to deal with the environmental concerns over, for example energy, is a necessity. There is an opinion that the environmental concerns of the energy chain are some of the most important drivers to influence European Union (EU) energy policy. Similarly, Renewable Energy Sources (RES) and energy efficiency created the stance for a sustainable energy system. The target for energy from RES (RES-E) in the gross final consumption in the Republic of Serbia is set to increase from 20.1% in 2014 to 27% in 2020. Each deviation from mandatory share of RES in gross final consumption in the Republic of Serbia would mean higher energy gross consumption than anticipated and more capacities for energy generation from RES. Analysis is required from the aspect of energy system possibilities, the impact on mandatory national goals for energy share from RES in total gross final energy consumption and long-term interest of the Republic of Serbia. Key words: Environmental policy integration, Sustainable Development, Renewable Energy Sources.

ANALYSIS OF THE USE OF FUEL BY HOUSEHOLDS AND NON-INDUSTRIAL CONSUMERS

Purpose of the paper is to analyze the available statistical data on fuel consumption by population in every region of Ukraine. To identify similarities and differences in development trends the comparison of structure of final energy consumption in Ukraine and the world was done. The degree of distribution of individual heating systems in urban settlements and rural areas in 2015 is determined. Analysis of the use of the main types of fuel by households sector in regions of Ukraine is performed. The amount of fuel consumed by the population does not linearly depend on the share of individual heating systems in the region (this was shown by an example), therefore to develop strategy for extending the use of renewable energy sources (RES) in the households more factors will need to be considered. Ukrainian and world energy balance data for 2015 (item “Other” which includes residential sector, commerce and public services, agriculture, fishing, other consumers) on the consumption of four main types of fuel (coal and peat, oil products, natural gas, biofuels and waste) were compared. It was concluded that in Ukraine the proportion of basic fuels consumption corresponds to world trends. However, after analyzing the distribution of total final energy consumption certain differences were observed. Analysis of renewable energy sources use by sectors has demonstrated that the residential sector is the leader in renewable energy sources consumption both in the world and in Ukraine. In Ukraine statistical data on biofuel consumption is mainly based on information about firewood and wood biomass consumption. This explains the higher percentage of biofuel consumption in forested areas. It should also be noted that in Ukraine 32% of the wood used by population was sold to households by enterprises and 68% was obtained from self-preparation. Over the past decade consumption of biomass fuel for household needs in Ukraine has doubled, and it is increasingly replacing coal fuel, thus exerting a positive impact on the environment.

Key Trends and Application of Sustainability Rating Systems in the Hungarian Office Building Segment

Enhancing the sustainability of buildings and construction activities has become a key issue over the last decades. Since in the European Union, the construction industry is responsible for about the 40% of the total final energy consumption, around 36% of total CO2-emission, and 32% of total waste generation it is not surprising, that the ambitious energy and climate protection goals of the EU pose enormous challenges to the sector. Although in the relevant literature there is a lack of common understanding of what sustainable and green buildings are, several quantitative and qualitative methods regarding the assessment of buildings’ sustainability, and approaches suitable for the examination of economic, social and environmental effects of buildings and the built environment have been emerged. The goal of this paper is to highlight the main principles and characters of green and sustainable buildings found in the literature, to summarize the key characteristics of the most important voluntary certification schemes applied in the European Union, and to present the current trends in the Hungarian Office market segment regarding the use of green certifications.

Building energy audit, thermal comfort, and IAQ assessment of a school building: A case study

In France, the total heated surface area of educational buildings represents 19.5% of non-residential buildings, with an average total final energy consumption of 142 kWh/m2/y. Of this, the energy usage for heating is 97 kWh/m2/y. To save energy, building energy assessment seeks a trade-off between energy savings and the indoor environmental quality (IEQ) of the buildings. A long-term post-occupancy study was conducted on a two-story educational building with a total floor area of 3200 m2 located in Troyes, France. The Building Management System (BMS) programme was used to analyse the energy consumption for a period of three years from January 2015 to December 2017. Although the building complies with High Environmental Quality (HQE®) standards, the post-occupancy energy demand exceeded the predicted consumption levels owing to the auxiliary equipment. Furthermore, the indoor air quality (IAQ) was assessed by monitoring and analysing CO2 levels, which were satisfactory for 95% of occupancy period. Moreover, further investigations were performed in the building's foyer, area where indoor thermal comfort was assessed experimentally and numerically. Subjective evaluation was also conducted according to survey questionnaires completed by 41 students between the ages of 17 and 22. The results indicate that increasing the indoor temperature by 1 °C can improve the indoor thermal sensation but led to increased energy consumption of about 12%.

Analysis of Electric Energy Substitution Potential Based on Re-electrification Target

This paper analyzes the electric energy substitution potential on the basis of reelectrification target. First, various kinds of energy are covered into equivalent electricity in terms of the calorific value. Second, the total equivalent electricity is calculated according to the energy consumed by sectors. Third, the total final energy consumption is obtained by subtracting the transformation cost, loss and the non-energy usage consumption from the total primary energy supply. Finally, the expected electricity is obtained by multiplying the final energy consumption with the target of electrification rate and the potential of energy substitution is evaluated by subtracting current power from the expected electricity. Besides, the proposed scheme is applied to evaluate the potential of electricity energy substitution in 2020, 2030 and 2050 as examples.

Consultancy Centres and Pop-Ups as Local Authority Policy Instruments to Stimulate Adoption of Energy Efficiency by Homeowners

The housing sector is responsible for a more than a quarter of the total final energy consumption in the EU. As the majority (70%) of the EU-housing stock is owner occupied and largely consists of single family dwellings it is understandable that many countries focus their energy saving policies on homeowners. Complementary to the national policy frameworks, regional and local authorities implement locally based policy instruments targeting specific groups and individual homeowners. In order to enlarge the effectiveness of their policy instruments and to reach the energy saving goals, frontrunner local authorities in particular are searching for ways to reach homeowners. Consultancy centres and pop-ups can be a way to make individual homeowners more aware about their energy use and stimulate them to apply low carbon technologies. The research results not only show that a wide range of business models are available to develop, structure and organise these consultation centres and pop-ups, but also that they indeed could play an important role in accelerating the energy performance of owner occupied housing. Through a pop-up or consultancy centre, public and private parties can join their forces to reach, stimulate and support the individual needs and wishes of homeowners during their customer journey to realise an energy efficient dwelling.

Residential Electricity Consumption and Economic Growth in Algeria

Within the framework of the COP21 (Conference of the Parties) agreement, Algeria submitted its Intended Nationally Determined Contribution pledging to reduce carbon emissions by at least 7% by 2030. However, it will be a difficult task to reach this target as total final energy consumption has increased 32% from 2010 to 2014, with the major energy increases being related to electricity use in the residential sector. In this context, the relationship between residential electricity consumption and income is analyzed for Algeria in the period 1970–2013, by estimating a residential electricity consumption per capita demand function which depends on GDP per capita, its squared and cubed terms, the electricity prices, and the goods and services imports. An extended Autoregressive Distributed Lag model (ARDL) was adopted to consider the different growth patterns registered in the evolution of GDP. The estimate results show that the relationships between electricity use and GDP (in per capita terms) present an inverted N-shape, with the second turning point having been reached. Therefore, promoting growth in Algeria could be convenient to reduce the electricity consumption, as a higher income level may allow the use of more efficient appliances. Additionally, renewable energies may be adequate to increase the electricity production in order to cover the increasing residential demand.

Informing on Best Practices Using Design Builder and RET Screen to Calculate Energetic, Financial, and Environmental Impacts of Energy Systems for Buildings

Buildings represent 32% of total final energy consumption. In terms of primary energy consumption, buildings represent around 40% in most IEA countries (International Energy Agency). For such reason, strategies that lead to energy savings and greenhouse gases reduction are needed.
 This research aims to provide a methodology able to identify the best system configuration from a technical, economic and environmental point of view by using at the same time two energy software: Design builder, which is able to calculate buildings energy needs under dynamic conditions, and RETScreen, which allows feasibility analysis of clean energy projects.
 In order to assess the effectiveness of this operating procedure, a historical building has been modelled and a Combined Cooling, Heat and Power system based on an internal combustion engine has been chosen to ensure environmentally sound way.
 In this study it shows the application of the procedure to a case study as an historical building located in Orte City which is near Rome in Italy; the methodology could get a real preliminary analysis for choose the best active or passive system for improve the energy efficiency and environmental sustainability of existing buildings, also allowing a cost-benefit analysis useful for the concrete realization of the interventions studied.

Energy performance progress of the Dutch non-profit housing stock: a longitudinal assessment

Worldwide, buildings consume a large part of the total energy delivered. In the context of all the end-use sectors, buildings represent the largest sector with 39% of the total final energy consumption, followed by transport in the EU (European Union ). Policy targets and regulations are in force at the EU level to ensure the energy efficiency improvement of the building stock. This research seeks to provide insight into the energy performance progress, of the existing non-profit housing stock in the Netherlands, through the application of energy renovations. The non-profit housing stock comprises 30% of the housing market in the Netherlands and a large part of the policies towards a more efficient housing stock rely on the non-profit housing sector. To that end, we determine the energy renovation rate of the stock and the impact of the applied renovations on both the predicted and actual energy consumption. The difference of predicted and actual energy savings is analysed through longitudinal statistical modelling in renovated and non-renovated dwellings. Based on the knowledge gained on the renovation rates of the non-profit housing stock we compare and evaluate future renovation rates through dynamic building stock modelling and empirical data validation. In essence, we examine the effect that the improvement of thermo-physical characteristics of dwellings has on efforts to make the existing housing stock almost emission-neutral by 2050, as advocated by the European Commission since 2011. The renovation activity is expected to be greater than the construction and demolition activity in the future and as such we need to bring awareness to the actual impact and effectiveness of energy renovations.

The evaluation of the use of renewable energy resources

There have been many discussions in Lithuania about a strategy for reducing the impact of climate change. Members of the international community agree that reducing greenhouse gas emissions to the atmosphere is necessary to avoid dangerous climate change. The main greenhouse gas emissions from human activity are carbon dioxide. Carbon dioxide is mainly produced by combustion of fossil fuels, which are currently used: natural gas, coal, oil, peat, etc. Fossil fuels are still the main source of energy. The amount of energy produced and consumption from renewable energy sources (RES) is increasing both in Lithuania and in Europe. According to the Directive (2009/28/EU) Lithuania has a legally binding target in the year 2020. The share of renewable energy would account for at least 23% of the total final energy consumption of the country. The share of renewable energy would account for at least 10% of the final energy consumption in the transport sector. Lithuania achieved its target and this indicator was 23.9% in 2014. According to the Eurostat data, the share of RES produced from renewable energy sources in the total energy balance is increasing annually. In 2007 this indicator was only 4.7% and it has grown 4 times in 2016. The production of electricity from renewable energy sources satisfied the country’s energy demand by 18.9% in Lithuania. This is the best index so far. Wind energy is the most popular type of green energy, which has been growing at a rate of 5 times in this period. Promotion of the use of renewable resources is provided in the Republic of Lithuania Law on Renewable Energy and the long-term development of the use of renewable resources is provided for in the National Energy Strategy. At this moment Lithuania is a fuel importing country, but in the future Lithuania should produce about 70% of electricity itself. It is forecasted that in 2020 electricity generation in the country should make up 35% of the demand, in 2030 it should be 70%, and in 2050 it should reach 100%. From renewables we should receive a large, almost 80% share of energy. And gas will be a transitional fuel by 2050. The project of strategy states that energy from renewable sources will become a major component of all sectors: electricity, heat, cooling and transport. The objective is to achieve a 30% share of renewables in the final energy consumption balance in 2020, 45% in 2030, and 80% in 2050. The renewables should produce all heat energy and the share of green energy in transport should reach 50% at the end of 2050. The article focuses on the use of the potential of renewable energy sources from agricultural raw materials and their waste. The surplus of agricultural production makes it necessary to look for opportunities to reduce environmental pollution. The aim of the article is to assess the use of potential of renewable energy sources in Lithuania. The results of the analysis showed that increasing energy production is possible not only using wind, solar, water or geothermal energy, but by processing traditional agricultural and animal products and their waste: straw, grain crops, livestock or bird’s excrement, etc. It is recommended to look at the unconventional potential of raw materials, such as sewage sludge, spirits, molasses, etc. The use of biomass has potentially revealed alternatives to biofuels that underpin the use of different generations of biofuels. The use of biofuels in the long term should contribute to the slowdown in climate change.

Analysis on energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy and China Dream target

A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy (2016–2030) and long-term economic and social development target China Dream. Results showed that 1) toward the 2050 China Dream target, total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050, whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050; 2) the proportion of non-fossil fuels is expected to reach approximately 50% and that of natural gas to reach more than 16% by 2050; 3) CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.

Potential biodiesel production from palm oil, coconut oil and soybean oil for Thailand

The government began subsidizing the use of B20 in large trucks on a voluntary basis beginning in 2016 and intends to implement the B10 requirement in 2018 for all diesel sales. However, policy makers in both the MOE and the Ministry of Agriculture and Cooperatives (MOAC) recently agreed that the mandatory biodiesel consumption plan for 2036 may be unattainable (given the strategy does not permit reliance on imports) and is therefore being reexamined. Despite an increase in harvested area, crude palm oil (CPO) production, the only feedstock used for biodiesel in Thailand, stagnated at 1.8-2.0 million from 2014-2016 due to unfavourable weather conditions. Thailand experiences a great economic and industrial development and is the second largest energy consumer in South East Asia. Being a net oil importer, Thai government has declared a renewable energy development programme in order to secure sustainable development and energy security. Thailand spends more than 10% of GDP for energy imports and transport sector accounts for 36% of total final energy consumption of which 50% is diesel. Diesel marks a huge impact on Thai economy.

Energy performance progress of the Dutch non-profit housing stock: a longitudinal assessment

Worldwide, buildings consume a large part of the total energy delivered. In the context of all the end-use sectors, buildings represent the largest sector with 39% of the total final energy consumption, followed by transport in the EU (European Union ). A considerable percentage of this energy consumption is attributed to the residential sector. The building sector plays a major role in order to meet the energy saving targets set in the EU and in the Netherlands. This is particularly true for existing buildings, because they will constitute the major part of the housing stock over several decades. The renovation activity is expected to be greater than the construction and demolition activity in the future. Policy targets and regulations are in force at the EU level to ensure the energy efficiency improvement of the building stock. The Energy Performance of Buildings Directive ([EPBD] 2002, recast 2010) is the main legislative and policy tool in EU and focuses on both new and existing buildings. At the same time, the building sector plays a prominent role in the Energy Efficiency Directive ([EED] 2012). Relatedly, in the Netherlands, the foundation of energy efficiency policy has been a number of national cross-cutting measures and EU derived policies that play a large role; like the strengthening of standards for new buildings or dwellings and energy labels for existing ones. The focus of this research is the existing dwelling stock and its energy performance progress. Throughout Europe, national approaches to building stock monitoring have evolved separately. Nevertheless, monitoring the building stocks’ energy performance is gaining attention. Information about the progress of energy performance improvements is not only needed to track the progress of policy implementation, but also better information and data are necessary to help the development of roadmaps towards a more energy efficient building stock. This research seeks to provide insight into the energy performance progress, of the existing non-profit housing stock in the Netherlands, through the application of energy renovations. The non-profit housing stock comprises 30% of the housing market in the Netherlands and a large part of the policies towards a more efficient housing stock rely on the non-profit housing sector. To that end, we determine the energy renovation rate of the stock and the impact of the applied renovations on both the predicted and actual energy consumption. The difference of predicted and actual energy savings is analysed through longitudinal statistical modelling in renovated and non-renovated dwellings. Based on the knowledge gained on the renovation rates of the non-profit housing stock we compare and evaluate future renovation rates through dynamic building stock modelling and empirical data validation. In essence, we examine the effect that the improvement of thermo-physical characteristics of dwellings has on efforts to make the existing housing stock almost emission-neutral by 2050, as advocated by the European Commission since 2011.

Unravelling the potential of energy efficiency in the Colombian oil industry

The oil and gas sector represents 39% of the world's total industrial final energy consumption, and contributes to around 37% of total greenhouse gas (GHG) emissions. This study investigates the potential for improvements in energy efficiency, and their implications for CO2 abatement, in the Colombian oil industry value chain. It also assesses the potential cost of conserved energy and mitigated CO2-eq. A bottom-up approach was used to identify energy efficiency measures based on an assessment of specific operational data at the process unit level. In total, 20 measures and technologies were identified and applied in 48 cases throughout the chain, representing energy savings of 15.8 PJ and GHG savings of 0.75 Mt CO2-eq per year. This accounts for 25% and 19% of the total energy consumption and GHG emissions, respectively. Ninety-six percent of the total energy savings come from measures that are already cost-effective and could be implemented in the short term. The results of this study offer a better understanding of the critical stages for energy and GHG savings potentials, as well as investment cost and revenue from a full value chain perspective, based on operational data processing.

Analysis of Energy Utilization Index in Thailand Sanitary Ceramics Sector

The growth in Thailand industrial sector energy use is particularly significant increased. In 2015, this sector accounts for a 36% of the total final energy consumption. The ceramic sanitary industries, which is one of these industrial sectors, consume much energy. It also has the potential and readiness to reduce energy consumption, both electricity and thermal. Therefore, this research aims to evaluate the energy utilization index of ceramic sanitary industries in Thailand from 2014 to 2015. The results of the studies will be identifying energy conservation opportunities at a sanitary ceramics sector through energy baseline compared with that of same industrial sector. The energy consumption data of the ceramics sanitary production would be applied by multiple linear regression to analyze factors, which affect the energy consumption of these industries. The result is a linear equation consistency with energy consumption and major factors is electricity energy used in the production system and minor factors also influence but less than the major factors include thermal energy used in a production system, number of employees and quantity of product.

Big data GIS analysis for novel approaches in building stock modelling

Building heat demand is responsible for a significant share of the total global final energy consumption. Building stock models with a high spatio-temporal resolution are a powerful tool to investigate the effects of new building policies aimed at increasing energy efficiency, the introduction of new heating technologies or the integration of buildings within an energy system based on renewable energy sources. Therefore, building stock models have to be able to model the improvements and variation of used materials in buildings. In this paper, we propose a method based on generalized large-scale geographic information system (GIS) to model building heat demand of large regions with a high temporal resolution. In contrast to existing building stock models, our approach allows to derive the envelope of all buildings from digital elevation models and to model location dependent effects such as shadowing due to the topography and climate conditions. We integrate spatio-temporal climate data for temperature and solar radiation to model climate effects of complex terrain. The model is validated against a database containing the measured energy demand of 1845 buildings of the city of St. Gallen, Switzerland and 120 buildings of the Alpine village of Zernez, Switzerland. The proposed model is able to assess and investigate large regions by using spatial data describing natural and anthropogenic land features. The validation resulted in an average goodness of fit (R2) of 0.6.

Effect of the placement of aerogel insulation in the heat transfer properties

Nowadays, the thermal insulation both of existing and new buildings is one of the most important actions for reducing the energy loss of buildings and to reduce the emission of green house gases. In the European Union, buildings account for about 20–40% of the total final energy consumption. Examination of the thermal properties (e.g., effective thermal conductivity) of building materials and structures are very important both for the manufacturers and for the consumers. Several possibilities are available for measuring this parameter of materials. The mainly used thermal insulating materials are the plastic foamy and mineral wool materials; moreover, the nanotechnological insulators (e.g., aerogel, hollow nanospheres) are requiring spaces for themselves also. One promising them for the future is the silica aerogel-based slabs. Aerogels are nanoporous lightweight materials that were discovered more than 70 years ago. Nowadays, their applications are truly widespread. Firstly, in this article thermal transmittance measurements of wall structures will be presented with calibrated chamber method. These measurements were accomplished through an inbuilt plaster/brick/plaster wall construction individually. After that, it was covered with a 0.013-m-thick aerogel layer at first in a cold and then in the warm side. Comparison of the heat fluxes, insulation capabilities and effective thermal conductivities measured by the above-mentioned method will be presented. The change in the retardation time and in the surface temperatures will be also discussed. Secondly, in order to investigate the conductive effect, thermal conductivity measurements with Holometrix lambda 2000 apparatus were accomplished too.

Income and Energy Consumption in Asia A Panel Cointegration Analysis with Common Factors

The research presented in this paper studies the relationship between energy consumption and income for a panel of Asian economies. The Asian economies represent a dynamic, diverse, and interesting set of countries on which to base an examination of these relationships and the tendencies for these economies to be on a path of convergence and integration in their energy consumption and use characteristics. We start with an overview of the evolution of energy intensities for the individual countries in our study. Panel data methodologies are then employed to gain the advantage of increased explanatory power of the econometric analysis results from pooling time series and cross-section observations. In addition, our panel cointegration analyses incorporate common factors as a means of accounting for variables beyond the bivariate relationship between income and total final energy consumption. The results find support for the flow of causality running from income to energy consumption, albeit with feedback. The results are consistent with and supportive of the findings of the seminal paper by Kraft and Kraft (1978). In addition, the long-run income elasticity estimates for the panel find that the estimates are very sensitive to the inclusion or exclusion of common factors.

Design, Implementation and Demonstration of Embedded Agents for Energy Management in Non-Residential Buildings

With the building sector being responsible for 30% of the total final energy consumption, great interest lies in implementing adequate policies and deploying efficient technologies that would decrease this number. However, building comfort and energy management systems (BCEM) are challenging to manage on account of their increasing complexity with regard to the integration of renewable energy sources or the connection of electrical, thermal and gas grids. Multi-agent~systems (MAS) deal well with such complex issues. This paper presents an MAS for non-residential buildings from the design, implementation and demonstration, both simulation based and in a field test. Starting from an ontology and an attached data model for BCEM application, we elaborated use cases for developing and testing the MAS framework. The building and technical equipment are modeled using the modeling language Modelica under Dymola. The agents are programmed in JADE and communicate with Dymola via TCP/IP and with the real devices via BACnet. Operatively, the~agents can take on different control strategies: normal operation with no optimization, optimization of energy costs, where energy is delivered through the room through the devices that have the lowest operating costs, and relaxation of the comfort constraint, where the costs of the productivity loss under sub-optimal comfort conditions is taken into account during optimization. Comfort is expressed as a function of indoor air temperature. Simulation, including a comparison with a benchmark system, and field test results are presented to demonstrate the features of the proposed BCEM.