Recognising the potential for renewable energy heating and cooling

Heating and cooling in the industrial, commercial, and domestic sectors constitute around 40–50% of total global final energy demand. A wide range of renewable energy heating and cooling (REHC) technologies exists but they are presently only used to meet around 2–3% of total world demand (excluding from traditional biomass). Several of these technologies are mature, their markets are growing, and their costs relative to conventional heating and cooling systems continue to decline. However, in most countries, policies developed to encourage the wider deployment of renewable electricity generation, transport biofuels and energy efficiency have over-shadowed policies aimed at REHC technology deployment. This paper, based on the findings of the International Energy Agency publication Renewables for Heating and Cooling—Untapped Potential, outlines the present and future markets and compares the costs of providing heating and cooling services from solar, geothermal and biomass resources. It analyses current policies and experiences and makes recommendations to support enhanced market deployment of REHC technologies to provide greater energy supply security and climate change mitigation. If policies as successfully implemented by the leading countries were to be replicated elsewhere (possibly after modification to better suit local conditions), there would be good potential to significantly increase the share of renewable energy in providing heating and cooling services.     

冷热电联产系统的发展及前景

1前言能源的价格、电网的稳定性、能量的品质、空气的品质以及全球气候的改变,是21世纪我们面临的严重问题。随着经济和社会的发展,这些问题将变得更加尖锐。在传统的利用燃料产生电力的过程中,将近三分之二的输入能量没有有效利用就被释放到环境中,能量损失十分严重。利用总能     

Internalising external costs of electricity and heat production in a municipal energy system

Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU′s ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument.     

Solar space heating and cooling for Spanish housing: Potential energy savings and emissions reduction

An experimental solar energy facility was designed to meet as much of the heating demand in a typical Spanish dwelling as possible. With a view to using the facility during the summer and preventing overheating-induced deterioration of the solar collectors in that season of the year, an absorption chiller was fitted to the system to produce solar-powered air conditioning. The facility operated in solar space heating mode in the winter of 2008–2009 and in cooling mode during the summer of 2008. The design was based on a new type of flat plate vacuum solar collectors that delivered higher efficiency than conventional panels. This type of collectors can reach temperatures of up to 110 °C in the summer and up to 70 °C on the coldest winter days. The solar facility comprised a 48-m² (with a net area of 42 m²) solar collector field, a 25-kW plate heat exchanger, a 1500-l storage tank, a 4.5-kW (Rotartica) air-cooled absorption chiller and several fan coils. The facility was tested by using it to heat and cool an 80-m² laboratory located in Madrid. As the average area of Spanish homes is 80 m², the findings were generally applicable to national housing. The solar facility was observed to be able to meet 65.3% of the space heating demand. For air conditioning, the system covered 46% of the demand, but with high indoor temperatures. In other words, the collector field was found to be able to air condition only half of the home (40 m²). Lastly, the savings in CO₂ emissions afforded by the use of this facility compared to conventional air conditioning were calculated, along with its amortisation period. These results have been extrapolated calculating the potential energy savings and emissions reduction for all the Spanish households.     

A new combined cooling, heating and power system driven by solar energy

A new combined cooling, heating and power (CCHP) system is proposed. This system is driven by solar energy, which is different from the current CCHP systems with gas turbine or engine as prime movers. This system combines a Rankine cycle and an ejector refrigeration cycle, which could produce cooling output, heating output and power output simultaneously. The effects of hour angle and the slope angle of the aperture plane for the solar collectors on the system performance are examined. Parametric optimization is conducted by means of genetic algorithm (GA) to find the maximum exergy efficiency. It is shown that the optimal slope angle of the aperture plane for the solar collectors is 60° at 10 a.m. on June 12, and the CCHP system can reach its optimal performance with the slope angle of 45° for the aperture plane at midday. It is also shown that the system can reach the maximum exergy efficiency of 60.33% under the conditions of the optimal slope angle and hour angle.     

the absorption process for heating,cooling and energy storage—an historical survey

The principle of the absorption process is described and its versatility demonstrated. A wide range of applications, from household refrigerators to topping processes in power plants, are surveyed in an historical perspective. the production of mechanical energy and open systems are also included. Modern developments are reviewed, special attention being given to the aspets of thermal energy storage.     

Simulation of a solar heating and cooling system

This paper presents thermal and economic analyses of a solar heated and air conditioned house in the Albuquerque climate. The system includes the following components: water heating collector, a water storage unit, a service hot water facility, a lithium bromide-water air conditioner (with cooling tower), an auxiliary energy source, and associated controls. The analysis of the thermal performance indicates the dependence of output on collector area (considered as the primary design variable) and shows, for example, the manner in which annual system efficiency decreases as collector area increases. Based on the computed thermal performance, cost estimates are made which show variations in annual cost as functions of collector area and costs of collector and fuel.     

生物质能用于热电冷三联供系统的可行性

生物质技术与热电冷三联供系统都是当前具有广阔发展前景的技术。通过对两者工作原理的介绍,简要分析了生物质作为一次能源用于热电冷联供系统的可行性,并指出了有待于进一步研究的一些方面。     

生物质分布式热电冷供给系统工程技术模式设计

以山东省淄博市周村区和平社区为例,针对该区域生物质资源多元化的特点,以现有研究成果和技术开发为基础,提出了一整套新农村生物质分布式热电冷供给系统工程技术模式,分析了实施该能源供给系统的经济、环境、社会效益。分析结果显示：实施生物质分布式热电冷供给系统工程,在彻底消除生物质废弃物产生的环境污染的同时,实现了区域能源自给,形成完整的区域能源循环经济模式,其经济、环境、社会效益显著。     

Economics of a solar-assisted heating/cooling system for an aquatic centre in a tropical environment

The paper reports on a feasibility study of a solar-powered heating/cooling system for a swimming pool/space combination in a tropical environment. The system employs an absorption chiller and a cooling tower to meet the locker-room load. The heating is accomplished by employing hot water generated by heat exchange with the solar collector working fluid. Two thermal storage tanks are employed for the collector and domestic use. The absorption chiller utilizes hot water to regenerate the LiBr solution. The proposed system will enable the swimming season to be extended from 16 weeks to 52 weeks. The economic analysis is performed based on the life-cycle-cost method. The effects of discount rate, fuel prices, and the fuel inflation rate are discussed. The analysis shows, with the present level of fuel prices, that the solarassisted system is not economical enough over a life cycle of 10 years. The study presents different scenarios for which the solar-assisted system is, however, economical.     

Efficiency of solar energy use for residential heating and cooling

The possibility of using solar energy collected on flat plate collectors situated on roofs for residential space heating/cooling and domestic water heating is considered. The study is carried out on a typical house situated in various locations in Libya. Two types of constructions involving heavy and light insulation, three roof tilts, and three values of system efficiency are considered. The study shows that the demand in a great part of the country can be provided from solar energy by a medium efficiency system, even with light insulation and a horizontal roof. Only in a few locations should the roof be tilted at an angle of 10 °. For a low-efficiency system, insulation is necessary; for a high-efficiency-system, it was found that there is no need for either heavy insulation or tilting of the roof.     

考虑冷热电互补及储能系统的多园区综合能源系统协调优化调度

新能源出力和用户负荷的随机性使得综合能源系统的优化调度问题充满挑战,本工作提出一种考虑冷热电互补及储能系统的多园区综合能源协调优化调度方法.首先,引入虚拟电厂技术,将综合能源系统内部资源聚合,考虑园区内的能量储存装置以及园区间的能量传输装置,构建虚拟电厂框架下的多园区综合能源系统结构;其次,建立热电联供单元、储能系统、...     

天然气三联供系统为数据中心供能的优势分析

提出采用天然气三联供系统取代传统方式为数据中心供能,以北京某机房为例,设计典型应用方案及运行模式,通过比较分析得到:三联供系统供能可靠性不低于传统供能方式;每年可节约标准煤24.6%,减排CO_238.4%;初始投资明显增加,但年运行成本降至约75%,整个生命周期能源成本大大降低。天然气三联供系统为数据中心供能可行且优势明显,建议推广应用。     

Scenario analysis of the energy demand and CO2 emission reduction potential of the urban transport system of Beijing through 2030

An assessment of the energy demand and the potential for sector-based emission reductions will provide necessary background information for policy makers. In this paper, Beijing was selected as a special case for analysis in order to assess the energy demand and potential of CO₂ abatement in the urban transport system of China. A mathematical model was developed to generate three scenarios for the urban transport system of Beijing from 2010 to 2030. The best pattern was identified by comparing the three different scenarios and assessing their urban traffic patterns through cost information. Results show that in the high motorization-oriented pattern scenario, total energy demand is about 13.94% higher, and the average CO₂ abatement per year is 3.38 million tons less than in the reference scenario. On the other hand, in the bus and rail transit-oriented scenario, total energy demand is about 11.57% less, and the average CO₂ abatement is 2.8 million tons more than in the reference scenario. Thus, Beijing cannot and should not follow the American pattern of high motorization-oriented transport system but learn from the experience of developed cities of Europe and East Asia.     

Performance of an experimental ground-coupled heat pump system for heating,cooling and domestic hot-water operation

The ground-coupled heat pump (GCHP) system is a type of renewable energy technology providing space heating and cooling as well as domestic hot water. However, experimental studies on GCHP systems are still insufficient. This paper first presents an energy-operational optimisation device for a GCHP system involving insertion of a buffer tank between the heat pump unit and fan coil units and consumer supply using quantitative adjustment with a variable speed circulating pump. Then, the experimental measurements are used to test the performance of the GCHP system in different operating modes. The main performance parameters (energy efficiency and CO₂ emissions) are obtained for one month of operation using both classical and optimised adjustment of the GCHP system, and a comparative analysis of these performances is performed. In addition, using TRNSYS (Transient Systems Simulation) software, two simulation models of thermal energy consumption in heating, cooling and domestic hot-water operation are developed. Finally, the simulations obtained using TRNSYS are analysed and compared to experimental data, resulting in good agreement and thus the simulation models are validated.     

Simulation of an absorption heat pump solar heating and cooling system

An absorption heat pump (AHP) is a heat driven heat pump utilizing the absorption process. A continuous, liquid absorbent AHP with chemical storage is modeled using mass and energy balances and assuming mass transfer equilibrium. This model is used with the TRNSYS program [5] to simulate the performance of an AHP in a residential solar-driven heating and cooling system. The effects of collector area for an AHP using the NaSCN---NH₃ chemical system are investigated for the Columbia, MO, Madison, WI, and Fort Worth, TX climates. The AHP system is compared to a conventional solar heating and cooling system and the effects of heat exchanger effectiveness, storage mass, additional thermal capacitance and alternative control strategies are studied for the Columbia climate.