Thermal comfort assessment and energy consumption analysis of ground-source heat pump system combined with radiant heating/cooling

A new ground source heat pump system combined with radiant heating/cooling is proposed, and the principles and the advantages of the system are analyzed. A demonstration of the system is applied to a rebuilt building： Xijindu exhibition hall, which is located in Zhenjiang city in China. Numerical studies on the thermal comfort and energy consumption of the system are carded out by using TRNSYS software. The results indicate that the system with the radiant floor method or the radiant ceiling method shows good thermal comfort without mechanical ventilation in winter. However, the system with either of the methods should add mechanical ventilation to ensure good comfort in summer. At the same level of thermal comfort, it can also be found that the annual energy consumption of the radiant ceiling system is less than that of the radiant floor system.

Analyses of influence of residential buildings' space organization on heating energy consumption in Lhasa

The heating load simulation models of the residential buildings in Lhasa are established for enhancing the space organization’s adaptability to climate and radiation and improving its energy saving performance.The space organization items a e analyzed for both the existing buildings without insulation and new buildings with good insulation.The items include orientation design,south a d north balcony design,the north and south partition wall’s position design,storey height design and window-wall ratio design.Simulation results show that orientation is the key design element for energy saving design,and adverse orientation can obviouslyincrease heating energy consumption;south and north balconies can reduce winter heating energy consumption;partition walls move to the north,which means that the south room’s big depth design leads to less heating energy consumption,but the effect is not inconspicuous;smaier storey height results in less heating load.For the existing buildings,the window-wall ratio of south side has a balance point for energy saving design in the calculation condition.For the new buildings with good insulation,enlarging the south window-wal ratio can continuously reduce heating energy consumption,but the energy saving rate between models gets smaier.The heating energy consumption comparison study between the common model and optimal space design model demonstrates that the energy saving design can significantly reduce heating energy consumption

Impact of summer office set air-conditioning temperature on energy consumption and thermal comfort

To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.

The Energy Consumption of Heatingin the Northeast Rural Area of China from the Perspective of the Kang and Agricultural Waste

In China, the heating energy consumption patterns of rural housing are changing due to economic development. This study investigated domestic heating in rural areas of Dalian, a city in northeast China. In rural areas of the country, heating devices such as coal boiler, radiator, and/ or air-conditioner are typically used. The Kang, as the main heating system, has been used together with other heating methods for a long time in detached houses, one-story buildings, and quadrangles. Use of the Kang in collective housing is no longer observed. In addition to coal, agricultural wastes have been used to fuel the Kang; the associated CO2 emissions with agricultural fuels are lower than from other heating equipment. Even when a combination of the Kang and other equipment is used, with agricultural waste as fuel, CO2 emissions remain relatively low.

Evaluation of Energy Consumption for Heating of Industrial Building in-Situ

Because of the high energy demand required to heat a production hall, the aim of this project is to find out whether it is possible to verify the heating consuming process for heating with the standard simplified calculation method [1], especially for cold regions such as Kosice (Slovakia). The energy requirement for heating a case study industrial building was evaluated using measurements and calculations.During the winter period, energy consumption was measured in the selected industrial building according to a validation standard [2]. The building is comprised of two halls. The measurements were analyzed according to the criteria used for validating residential and public buildings, with several regression dependencies taken into account in the resulting evaluation of heating energy consumption. The mathematical dependencies of measured values in real conditions are shown in this paper. In addition, the building’s heating energy demand was calculated according to the Austrian standard [3], ?NORM EN ISO 13790, the simplified calculation method for non-residential buildings. It was investigated whether the measured values could be replicated using this calculation. It was found that the precise definition of the internal heat gains is very important.

Economic feasibility and efficiency enhancement approaches for in situ upgrading of low-maturity organic-rich shale from an energy consumption ratio perspective

The technical feasibility of in situ upgrading technology to develop the enormous oil and gas resource potential in low-maturity shale is widely acknowledged.However,because of the large quantities of energy required to heat shale,its economic feasibility is still a matter of debate and has yet to be convincingly demonstrated quantitatively.Based on the energy conservation law,the energy acquisition of oil and gas generation and the energy consumption of organic matter cracking,shale heat-absorption,and surrounding rock heat dissipation during in situ heating were evaluated in this study.The energy consumption ratios for different conditions were determined,and the factors that influence them were analyzed.The results show that the energy consumption ratio increases rapidly with increasing total organic carbon(TOC)content.For oil-prone shales,the TOC content corresponding to an energy consumption ratio of 3 is approximately 4.2%.This indicates that shale with a high TOC content can be expected to reduce the project cost through large-scale operation,making the energy consumption ratio after consideration of the project cost greater than 1.In situ heating and upgrading technology can achieve economic benefits.The main methods for improving the economic feasibility by analyzing factors that influence the energy consumption ratio include the following:(1)exploring technologies that efficiently heat shale but reduce the heat dissipation of surrounding rocks,(2)exploring technologies for efficient transformation of organic matter into oil and gas,i.e.,exploring technologies with catalytic effects,or the capability to reduce in situ heating time,and(3)establishing a horizontal well deployment technology that comprehensively considers the energy consumption ratio,time cost,and engineering cost.

A Survey on a Heat Exchangers Network to Decrease Energy Consumption by Using Pinch Technology

There are several ways to increase the efficiency of energy consumption and to decrease energy consumption. In this paper. the application of pinch technology in analysis of the heat exchangers network （HEN） in order to reduce the energy consumption in a thermal system is studied. Therefore, in this grass root design, the optimum value of △Tmin, is obtained about 10℃and area efficiency （a） is 0.95. The author also depicted the grid diagram and driving force plot for additional analysis. In order to increase the amount of energy saving, heat transfer from above to below the pinch point in the diagnosis stage is verified for all options including re-sequencing, re-piping, add heat exchanger and splitting of the flows. Results show that this network has a low potential of retrofit to decrease the energy consumption, which pinch principles are planned to optimize energy consumption of the unit. Regarding the results of pinch analysis, it is suggested that in order to reduce the energy consumption, no alternative changes in the heat exchangers network of the unit is required. The acquired results show that the constancy of network is completely confirmed by the high area efficiency infirmity of the heat exchanger to pass the pinch point and from of deriving force plot.

Conflict between Population and Urbanization Factors： Impact of Urban Heat Island on Energy Consumption Balance

High density of buildings and population in urban areas increases urban temperature, generally known as the urban heat island. Raised temperature, especially in SUlIuner, alms city centers into unwelcome hot areas, with direct effects on electricity demand and energy consttrnption for cooling buildings and increases the production of carbon dioxide and other pollutants. Therefore, by considering that the energy consumption in the world has been faced with intense crisis, it becomes increasingly important to study the effects of urban heat island on energy constunption in order to improve people＇s environment and decrease energy use in cities. This paper, therefore, is focused on urbanization and population size factors to understand tile influence way of these factors on formation of UHI and energy consumption balance. To achieve this aim, this paper explores literally the conceptual framework of confliction between population and urban structure, which produce UHI intensity and affected energy consumption balance. It is then discussed how these two factors can be affected and give implication to the city, and then, focuses on whether actions should be taken for balancing adaptation and mitigation UHI effects. It will be concluded by making the recommendations for preventive action and provide quality of life.

Based on the water source heat pump system operation control and energy consumption optimization

The contradiction between the increasing material demand and resource,is the country has faced problems,to better solve the material demand and the contradiction between the environment and resources,is applied to the development of new energy,new energy,not only can alleviate people and resources,environment and resources,the contradiction between people and the environment,also can promote the sustainable development of world economy,HVAC technology has emerged a new generation of energysaving technology,HVAC has the characteristics of low consumption,low pollution,is a development of technology,to be promoted for environmentfriendly,resource-conserving society has an important role in promoting.This paper focuses on the HVAC technology,water source heat pump system operation control and energy consumption optimization,for the relevant personnel reference.

Impact of Climate Change on Energy Consumption in North China

Based on the daily meteorological data with preliminary quality-control from 94 meteorological stations in North China during 1961 -2009, the impact of climate change on energy consumption in North China was analyzed by calculating heating and cooling degree-day. It＇s shown that the heating degree-days （HDDs） in most areas of North China reduced obviously during 1961 -2009. The heating energy consumption tended to decrease with temperature rising and the reduction rate in the northern region was greater than that in the southern region. The cooling degree-days （CDDs） in most areas of North China in summer tended to increase. Besides the west of Inner Mongolia, the regions where the CDDs increased significantly in North China corresponded to the urban agglomerations of Beijing, Tianjin, Hebei and Shanxi. The rise in temperature made the cooling energy consumption increase greatly in most areas of North China in summer. The result from future climate projection reveals that the HDDs in most areas of North China will reduce persistently and the reduction rate in the northern region is also higher than that in the southern region. Simul- taneously, the CDDs in most areas of North China in summer will continue to increase. The increasing rate in the southern region is higher than that in the northern region, and the most obviously increasing regions are located in the west of Inner Mongolia, Beijing, Tianjin, middle-southern region of Hebei, and south of Shanxi. This reveals that the cooling energy consumption in most areas of North China in summer will significantly increase due to climate warming.

THEORETIC ENERGY CONSUMPTION OF NONFERROUS METALS BY VACUUM DISTILLATION

The expressions of heat of evaporation for metals at different temperatures were deduced from Clausius-Clapeyron equation and the total change of enthalpy.Those of Pb,Cd and Zn were calculated.Results showed that theoretic energy consumption decreased a little with the decrease of e-vaporation temperature,which can be used to determine the energy demand while these metals are distilled at different process temperatures and pressures.

Analysis on Technical Measures on Energy Saving and Consumption Reducing During Stevia Sugar Production

Based on the analysis of actual energy consumptions during stevia sugar production,practical measures were proposed to save energy（ gas,water and powder） consumption and reduce cost through waste heat recycle and utilization,process improvement,equipment operation efficiency,application of newly energysaving equipment,and some project applications were provided as case study for some techniques and methods adopted in the production.

Energy-efficient intermittent liquid heating of lithium-ion batteries in extreme cold using phase change materials

The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery performance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge–discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩwas observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80%owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94%with a reduction in capacity of only 0.8%compared to the continuous strategy.

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot water.The hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the system.This experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner laboratory.The hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ separately.The results showed that the system operated stably and reliably.This system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump system.Its energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

Application of Dual Throttling Air-Conditioning System to Explosion-Proof Frequency Converter

An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study investigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning system was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrigeration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0 ℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experimental data.

Space heating and hot water demand analysis of dwellings connected to district heating scheme in UK

To achieve CO2 emissions reductions, the UK Building Regulations require developers of new residential buildings to calculate expected CO2 emissions arising from their energy consumption using a methodology such as Standard Assessment Procedure （SAP 2005） or, more recently SAP 2009. SAP encompasses all domestic heat consumption and a limited proportion of the electricity consumption. However, these calculations are rarely verified with real energy consumption and related CO2 emissions. This work presents the results of an analysis based on weekly heat demand data for more than 200 individual fiats. The data were collected from a recently built residential development connected to a district heating network. A method for separating out the domestic hot water （DHW） use and space heating （SH） demand has been developed and these values are compared to the demand calculated using SAP 2005 and SAP 2009 methodologies. The analysis also shows the variation in DHW and SH consumption with size of flats and with tenure （privately owned or social housing）. Evaluation of the space heating consumption also includes an estimate of the heating degree day （HDD） base temperature for each block of fiats and compares this to the average base temperature calculated using the SAP 2005 methodology.

Duty Cycle of a Radiant Ceiling Heating System under Extremely Cold-Temperature Conditions:A Theoretical Assessment

This work focuses on the estimation of a duty cycle of a radiant ceiling heating system with a panel surface temperature of 35℃and a heat flux of 65 W/m2 that corresponds to a thermal comfort for sedentary occupants.The results obtained are based on the theoretical heat transfer equations that govern the radiant and natural convection heat exchange mechanisms,and experimental heat transfer coefficients available in the literature.The results of the examined radiant heating system with specific conditions showed that a duty cycle of 6.46 min alternated by 13.36 min in shutting-down position is required to assure an acceptable thermal comfort for the enclosure space occupants.In addition,the study showed that for extremely cold-temperature conditions the heating system requires a daily operating load of about 61.2%which clearly proves the efficiency of these radiant heating systems in terms of energy consumption.

基于机器学习的空气源热泵干燥能耗回归预测

为了降低空气源热泵干燥过程能耗,研究了空气源热泵干燥能耗特性,采用多元线性回归模型(multivariate linear regression model, MLRM)和BP神经网络(back propagation neural network, BPNN)模型来预测干燥工艺能耗。在分析干燥能耗影响特征参数的基础上,提出将干燥工艺过程进行切分处理的方法以降低数据获取难度。选取烘房设定温度、烘房设定湿度、烘房初始温度、烘房初始湿度、环境平均温度、环境平均湿度、物料质量和初始含水率8个特征参数作为模型输入,能耗和物料结束含水率作为模型输出。使用MLRM模型、BPNN模型和其他机器学习模型进行能耗预测,MLRM模型对能耗拟合的决定系数为0.739,对物料结束含水率拟合的决定系数为0.931;BPNN模型使用Sigmoid函数作为激活函数时对能耗拟合的决定系数最高,为0.828,使用Identity函数作为激活函数时对物料结束含水率拟合的决定系数最高,为0.942,拟合效果优于其他机器学习模型,能够满足实际生产需求。以复水豌豆为干燥对象设计加载物料65 kg、持续时间4 h的完整变温变湿干燥工艺进行验证试验,结果表明:试验总能耗为15.066 kW·h,MLRM模型和BPNN模型的预测总能耗分别为14.476 kW·h、15.183 kW·h,预测精度分别为96.08%、99.23%;试验结束含水率为8.541%,MLRM模型和BPNN模型的预测结束含水率分别为9.560%、8.889%,预测精度分别为88.07%、95.93%。该研究提出了一种使用MLRM模型和BPNN模型对空气源热泵干燥能耗进行分段精准预测的有效手段,对于优化干燥工艺和降低干燥能耗具有实际意义。

某油田联合站污水余热利用研究

原油集输系统中的热化学沉降脱水,需要将原油温度升高,这一过程将消耗大量能源,其燃料主要为天然气,加热产生大量的CO_(2)。文中通过对某油田联合站生产流程研究分析,同时结合站内用热情况,确定采用压缩式热泵替代现有燃气加热炉技术路线,用于冬季采暖和一段原油加热。项目实施后,每年可节能源8932×10^(4) MJ,折合标煤减少3481.8 t,减少CO_(2)排放2024.5 t,每年可节省能源消耗费用651.8万元,节能减排效果显著,该研究对油田联合站清洁能源替代,减少CO_(2)排放具有重要意义。

寒冷地区农村居住建筑供暖能耗计算方法研究

分析了主要文献对多智能体的定义及其特征,对建筑环境与能源控制领域的多智能体控制系统应用的标准、常用框架和语言进行了综述和介绍,并对多智能体控制系统的不同系统架构、协调机制、优化算法进行了对比分析。针对建筑设备系统优化控制、单体建筑能源与环境优化控制、建筑与外部能源网络交互优化控制、建筑群与外部能源网络优化控制等不同层次的多智能体控制应用研究进行了综述,并对多智能体控制系统在建筑能源和环境领域应用中存在的时间序列优化、在线学习、计算不确定性、稳定性与收敛性等重要问题进行了讨论。