Technology line and case analysis of heat metering and energy efficiency retrofit of existing residential buildings in Northern heating areas of China

The building area in northern heating areas accounting for 70% of the total land area in China is 6,500,000,000 m². The average heating energy consumption in northern China is 100–200% times more than developed countries in the same latitude. This paper introduced firstly the heat metering and energy efficiency retrofit background of existing residential buildings in northern heating areas of China organized by mohurd and MOF, and then put forward the total principle and contents of retrofit. Through analyzing some retrofit cases in Germany, Poland and China, some technological experiences were summarized and finally a technology line suitable for heat metering and energy efficiency retrofit of existing residential buildings in northern heating areas of China which involved retrofit for heat metering and temperature regulation of heating systems, heat balance of heat source and network, and building envelope was described to provide a systematic, scientific, technological guide for the retrofit projects of 0.15 billion m² in “the Eleventh Five-Year Plan” period.     

Check and evaluation system on heat metering and energy efficiency retrofit of existing residential buildings in northern heating areas of china based on multi-index comprehensive evaluation method

Heat metering and energy efficiency retrofit of existing residential buildings in northern heating areas of China is organized and implemented in a large scale by local government in 15 provinces of North China with the unified guidance and control of central government. Firstly, this paper introduced the target of energy-saving reformation of existing residential buildings in North China and the importance of check and evaluation on this target, then pointed out the necessity of building up an evaluation system for energy-saving retrofit. According to the analytical hierarchy process (AHP), three-grade evaluation system was built up for heat metering and energy efficiency retrofit of existing residential buildings in northern heating areas of China. Also, based on multi-index comprehensive evaluation method combined with life cycle assessment (LCA) theory, post-evaluation thought and successful degree evaluation method, a mathematical model was established. Finally, a set of scientific method for evaluating heat metering and energy efficiency retrofit of existing residential buildings in northern heating areas of China systematically, scientifically, comprehensively and objectively was created.     

Pattern analysis and suggestion of energy efficiency retrofit for existing residential buildings in China's northern heating region

In China, Energy Efficiency Retrofit for Existing Residential Buildings (EERFERB) is faced with a fast development status. The Central Government decided to prompt the retrofit of 1.5×10⁸ m² existing residential buildings in China's northern heating region during the “11th Five-Years Plan”. But, at present, the relative incentive policies and measurements are very insufficient. Especially, on the aspect of the retrofit pattern about the organization, retrofit content, investing and financing mode, the policy and management and other factors, no existing successful one can be spreaded into the whole northern heating region. This research not only analyzed the foreign advanced methods, drew lessons from their retrofit in Germany and Poland, but contrasted and analyzed energy efficiency retrofit demonstrations from Harbin, Tianjin, Tangshan and Baotou in China to get our domestic successful patterns and experience. Finally, some recommended retrofit patterns are presented, which can be applied for the instruction and decision-making for the Chinese local governments.     

Fiscal and tax policy support for energy efficiency retrofit for existing residential buildings in China's northern heating region

Energy efficiency retrofit for existing residential buildings (EERERB) in China's northern heating region is an important component of the national energy strategy. The main content and related subject in EERERB performance is the basis of understanding and developing targeted policies. So, this paper designed the content system of EERERB. And then, provided a cost-benefit analysis on related subjects, assessed the government's function in EERERB, and come to the conclusion that the Chinese government should increase fiscal fund investment and implement more fiscal and tax incentive policies. Moreover, in view of China's current policy, which lacks long-term mechanism and flexibility, this paper proposed specific policy recommendations, including clarifying the government's corresponding responsibilities at all levels and increasing the intensity of the central government's transfer payments. It further proposed targeted financial and tax policies for supporting and encouraging heating enterprises and owners, as well as policies to cultivate energy-saving service markets and to support the ESCO.     

集中供暖热计量模式多样化的必要性分析

通过工程实例对我国节能建筑集中供暖热计量系统设计所存在的问题进行讨论。目前我国居住建筑集中供暖系统热计量设计模式单一,没有充分考虑我国国情和不同类型居住建筑的特点,加之我国的供热体制改革滞后,使得新建居住建筑的节能效果无法保证,还增加了工程建设费用。相关的技术规程予以补充和完善。     

Development of a new energy efficiency rating system for existing residential buildings

Building energy efficiency rating systems have been established worldwide to systematically manage the energy consumption of existing buildings. This study aimed to develop a new energy efficiency rating system for existing residential buildings from two perspectives: (i) establishment of reasonable and fair criteria for the building energy efficiency rating system; and (ii) establishment of comparative incentive and penalty programs to encourage the voluntary participation of all residents in the energy saving campaign. Based on the analysis of the conventional energy efficiency rating system for existing residential buildings, this study was conducted in five steps: (i) data collection and analysis; (ii) correlation analysis between the household size and the CO₂ emission density (i.e., CO₂ emission per unit area); (iii) cluster formation based on results of the correlation analysis using a decision tree; (iv) establishment of a new energy efficiency rating system for existing buildings; and (v) establishment of incentive and penalty programs using advanced case-based reasoning. The proposed system can allow a policymaker to establish a reasonable and fair energy efficiency rating system for existing residential buildings and can encourage the voluntary participation of all residents in the energy saving campaign.     

Target-oriented obstacle analysis by PESTEL modeling of energy efficiency retrofit for existing residential buildings in China's northern heating region

According to the “Comprehensive Work Program of Energy Efficiency and Emission Reduction” of the Chinese government, during the period of the “11th Five-Year Plan”, 1.5×10⁸ m² of existing residential buildings in China's northern heating region are to be retrofitted for energy efficiency. However, at present, this “Energy Efficiency Retrofit for Existing Residential Buildings” (EERFERB) faces many obstacles. Under the current working and market system, both the central and local governments and the energy supply companies can not push on this work smoothly. Using both the results of the annual national special inspection of building energy efficiency and some case analyses, this paper examines the necessity for energy efficiency retrofit, along with the relationships among the various Political, Economic, Social, Technological, Environmental and Legal (PESTEL) factors affecting it. Furthermore, organizational, financial and technical support systems are explored to promote the development of retrofit. Finally, some primary principles to be followed toward the implementation of EERFERB are suggested.     

Factors influencing energy efficiency investments in existing Swedish residential buildings

We used the data from a survey conducted in 2008 of 3,000 owners of detached houses to analyse the factors that influence the adoption of investment measures to improve the energy efficiency of their buildings. For the majority of Swedish homeowners, it was important to reduce their household energy use, and most of them undertook no-cost measures as compared to investment measures. Personal attributes such as income, education, age and contextual factors, including age of the house, thermal discomfort, past investment, and perceived energy cost, influence homeowners’ preference for a particular type of energy efficiency measure. The implications for promoting the implementation of energy efficiency investment measures are discussed.     

Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO₂ emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO₂ emissions in the analysed DH system.     

Incentive mechanism design for the residential building energy efficiency improvement of heating zones in North China

Starting with analyzing the investigation results by Ministry of Housing and Urban–Rural Development of China in 2005, more than half of the 10,236 participants are willing to improve the residential building energy efficiency and accept an additional cost of less than 10% of the total cost, the authors illustrate that incenting actions are necessary to improve building energy efficiency and build a central government–local government–market model. As a result of the model analysis, to pursue good execution effects brought by the incentive policies, the executors are required to distinguish the differences of incentive objects’ economic activities and strongly respect the incenting on the energy conservation performance. A case study on the incentive policies of existing residential building energy efficiency improvement in heating zones in North China is given as well. Finally, it is strongly recommended to give the first priority to performance-based incentives so that to reduce the lazy behaviors of the incented objects and ensure the targets to be achieved.     

A method of identifying and weighting indicators of energy efficiency assessment in Chinese residential buildings

This paper describes a method of identifying and weighting indicators for assessing the energy efficiency of residential buildings in China. A list of indicators of energy efficiency assessment in residential buildings in the hot summer and cold winter zone in China has been proposed, which supplies an important reference for policy makings in energy efficiency assessment in buildings. The research method applies a wide-ranging literature review and a questionnaire survey involving experts in the field. The group analytic hierarchy process (group AHP) has been used to weight the identified indicators. The size of survey samples are sufficient to support the results, which has been validated by consistency estimation. The proposed method could also be extended to develop the weighted indicators for other climate zones in China.     

Studies on the retrofit of heat exchanger network based on the hybrid genetic algorithm

The retrofit of heat exchanger networks (HENs) is an important branch of investigation for systematic heat integration. The studies on the economical and efficient retrofit techniques are very important for the high energy-consumption enterprises to save energy, protect environment and improve their market competitiveness. Because the retrofit of HEN is an optimization problem normally solved by a mixed integer nonlinear program (MINLP) which requires enormous solution space, it is very difficult to solve it with the traditional optimization methods. In this paper, by the analysis of an existing heat exchanger network, the hybrid genetic algorithm is applied to obtain the optimal retrofitted HEN with full utilization of the existing heat exchangers and structures. Two examples are taken to show the better effect of the retrofit method with the optimal new heat exchangers and re-piping cost and energy saving.     

Success factors of energy performance contracting (EPC) for sustainable building energy efficiency retrofit (BEER) of hotel buildings in China

Hotel building is a type of high-energy-consuming building and most existing hotel buildings need energy efficiency improvement in China. Energy performance contracting (EPC) is considered a win−win mechanism to organize building energy efficiency retrofit (BEER) project. However, EPC mechanism has been introduced into China relatively recently and many EPCs have not been successful in building energy efficiency retrofit projects. This research aims to develop a set of critical success factors (CSFs) of EPC for sustainable energy efficiency retrofit (BEER) of hotel buildings in China. Semi-structured interviews and a questionnaire survey with practitioners and other professionals were conducted. The findings reveal the relative importance of the 21 number of identified success factors. In order to explore the underlying relationship among the identified critical success factors (CSFs), factor analysis method was adopted for further investigation, which leads to grouping the 21 identified CSFs into six clusters. These are (1) project organization process, (2) EPC project financing for hotel retrofit, (3) knowledge and innovation of EPC, sustainable development (SD), and M&V, (4) implementation of sustainable development strategy, (5) contractual arrangement, and (6) external economic environment. Finally, several relevant policies were proposed to implement EPC successfully in sustainable BEER in hotel buildings.     

The energy saving obtainable with solar heating and heat pumps in a northern climate

The energy saving obtainable with active solar heating and heat pumps has been studied for several years in the Northern climate of Finland. The studies deal mainly with small houses. A computer program is developed which calculates hour by hour the annual energy balance of different heating systems. The performance, of the heating systems are also measured in inhabited houses. The calculations show that the useful solar energy obtainable from the collector is 50–400 kWh/m² annually depending on the system and the collector size. A heat pump in the system is very advantageous, because it keeps the heat losses low and the collector efficiency high. It approximately doubles the energy obtainable. The measurement results have not been as good as expected. The solar energy obtained from the collector has been 120–160 kWh/m² annually. The main reasons for the low solar energy are design and equipment faults and the shading effects. The best energy saving device is the earth heat pump. It is also therefore very advantageous that the peak power demand decreases markedly. When the area of the earth pipes is large enough, energy may be extracted from earth through the whole year. The annual coefficient of performance is 2–3. Also a heat pump which extracts heat from exhaust air in dwelling houses has been very promising.     

Application of intensified heat transfer for the retrofit of heat exchanger network

A number of design methods have been proposed for the retrofit of heat exchanger networks (HEN) during the last three decades. Although considerable potential for energy savings can be identified from conventional retrofit approaches, the proposed solutions have rarely been adopted in practice, due to significant topology modifications required and resulting engineering complexities during implementation. The intensification of heat transfer for conventional shell-and-tube heat exchangers can eliminate the difficulties of implementing retrofit in HEN which are commonly restricted by topology, safety and maintenance constraints, and includes high capital costs for replacing equipment and pipelines. This paper presents a novel design approach to solve HEN retrofit problems based on heat transfer enhancement. A mathematical model has been developed to evaluate shell-and-tube heat exchanger performances, with which heat-transfer coefficients and pressure drops for both fluids in tube and shell sides are obtained. The developed models have been compared with the Bell-Delaware, simplified Tinker and Wills-Johnston methods and tested with the HTRI® and HEXTRAN® software packages. This demonstrates that the new model is much simpler but can give reliable results in most cases. For the debottlenecking of HEN, four heuristic rules are proposed to identify the most appropriate heat exchangers requiring heat transfer enhancements in the HEN. The application of this new design approach allows a significant improvement in energy recovery without fundamental structural modifications to the network.     

Life-cycle energy of residential buildings in China

In the context of rapid urbanization and new construction in rural China, residential building energy consumption has the potential to increase with the expected increase in demand. A process-based hybrid life-cycle assessment model is used to quantify the life-cycle energy use for both urban and rural residential buildings in China and determine the energy use characteristics of each life cycle phase. An input–output model for the pre-use phases is based on 2007 Chinese economic benchmark data. A process-based life-cycle assessment model for estimating the operation and demolition phases uses historical energy-intensity data. Results show that operation energy in both urban and rural residential buildings is dominant and varies from 75% to 86% of life cycle energy respectively. Gaps in living standards as well as differences in building structure and materials result in a life-cycle energy intensity of urban residential buildings that is 20% higher than that of rural residential buildings. The life-cycle energy of urban residential buildings is most sensitive to the reduction of operational energy intensity excluding heating energy which depends on both the occupants' energy-saving behavior as well as the performance of the building itself.     

Research of heat metering development situation and application effect evaluation model in China

In spite of over 10 years of heat metering promotion in China, there still lays a certain gap between actual application and expectation. In this paper, the author conducts a comprehensive carding of China's current situation of heat metering in the aspects of policy, price, application area, technical roadmap, product quality and so on. An application effect evaluation model is established based on the geometric mean weights method. Assignments and weighs of factors in the model are achieved via multi-agent wide range of questionnaires. Comparisons are made among model results, results published by Liu Xin and the results released from the Ministry of Housing and Urban–Rural Development of the People's Republic of China (MOHURD), which proves rationality and high accuracy of the model established in this paper. Evaluation results show that application of heat metering in 2012 requires improvement with the score pegged at 60.7. It is suggested that policy support from national government should be strengthened, the impact of policies released by provincial government be curbed and heat metering pricing be increasingly reasonable. Application conditions of different metering techniques routes need to be clarified and relevant standards need to be revised to improve the operation.     

On the potential trade-offs between energy supply and end-use technologies for residential heating

In Sweden, where district heating accounts for a significant share of residential heating, it has been argued that improvements in end-use energy efficiency may be counter-productive since such measures reduce the potential of energy efficient combined heat and power production. In this paper we model how the potential trade-offs between energy supply and end-use technologies depend on climate policy and energy prices. The model optimizes a combination of energy efficiency measures, technologies and fuels for heat supply and district heating extensions over a 50 year period. We ask under what circumstances improved end-use efficiency may be cost-effective in buildings connected to district heating? The answer hinges on the available technologies for electricity production. In a scenario with no alternatives to basic condensing electricity production, high CO₂ prices result in very high electricity prices, high profitability of combined heat and power production, and little incentive to reduce heat demand in buildings with district heating. In contrast, in a scenario where electricity production alternatives with low CO₂ emissions are available, the electricity price will level out at high CO₂ prices. This gives heat prices that increase with the CO₂ price and make end-use efficiency cost-effective also in buildings with district heating.     

Efficiency of wind energy utilization for electricity and heat supply in northern regions of Russia

The paper describes a method for assessing the economic efficiency of wind energy utilization within small autonomous systems for both electricity and heat supply. The obtained analytical solution allows the simplification of calculations in comparison to the methods of chronological modeling and numerical algorithms for application of the convolution method.The economic effect of using wind turbines is assessed for remote communities of the extreme north of Russia with a maximum electric load of 200 kW for the turbines with a capacity from 30 to 800 kW, taking into account variation of possible growth rates of fossil fuel price for back-up sources of electric and heat energy.The calculations performed have shown that at the existing and forecasted rates of fuel price escalation, the economic effect of using surplus (as a result of mismatch in production and consumption) electric energy for heat supply will be 1.5–2.0 times higher. In this case, the optimal capacity of wind turbines can substantially exceed electric load power (two to four times).     

Regulating district heating in Romania: Legislative challenges and energy efficiency barriers

Many states in Eastern and Central Europe (ECE) possess extensive district heating (DH) networks that were constructed during the days of communist rule in order to provide a universally accessible energy service that supported Soviet development policies. But the post-communist transition was marked by the exacerbation of the sector’s numerous technical, economic, regulatory and environmental problems, accompanied by its abandonment in favour of alternative methods of domestic heating. Recent efforts to increase the use of DH in ECE as a result of environmental and energy security concerns have taken place in an absence of critical, context-sensitive research.