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1.
Applicability and optimum control strategy of energy recovery ventilators in different climatic conditions 总被引:1,自引:0,他引:1
Energy recovery ventilators (ERVs) transfer energy between the air exhausted from building and the outdoor supply air to reduce the energy consumption associated with the conditioning of ventilation air. In this paper, the applicability of ERVs with sensible and latent effectiveness values in a practical range is studied using TRNSYS simulation program. The impact of ERV on annual cooling and heating energy consumption is investigated by modeling a 10-storey office building in four American cities as representatives of major climatic conditions. The results show that heat and moisture recovery can lead to a significant reduction in the annual heating energy consumption (i.e., up to 40%, which is 5% higher than heat recovery). Also, an ERV with the capability of moisture recovery may reduce the annual cooling energy consumption by 20% provided the ERV is properly controlled. Since the un-controlled operation of ERVs during the summer may increase the cooling energy consumption, an optimum control strategy is developed and verified in the paper. This optimum control strategy depends on ERV's latent to sensible effectiveness ratio. For instance, an ERV with equal sensible and latent effectiveness should be operated when either the outdoor enthalpy or temperature is greater than that of the indoor air. 相似文献
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G. Mageshwaran G. Britto Joseph Tallapaneni Sivaji Vulchi Ravi Teja Maruthairaja 《国际自然能源杂志》2018,39(7):719-725
Nowadays, global warming, environment pollution, and limitations in energy resources have appeared as a serious global crisis. Therefore, energy efficiency and energy conservation are necessary in all energy-consuming devices, such as heating, ventilating, and air conditioning (HVAC) systems. The aims of this project are to evaluate the performance and energy conservation of a conventional air conditioning system and also compare its performance with the proposed HVAC system, which consists of a heat recovery unit to reduce the initial capital cost and electricity consumption of the system. Through hour-by-hour simulations, the annual energy consumptions of these two systems have to be calculated and analysed. A CO2-based demand controlled ventilation strategy offers a great opportunity to reduce additional energy consumption in the above HVAC systems, while providing the required ventilation. 相似文献
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Y.H. Yau 《Energy and Buildings》2008,40(5):917-925
In two earlier papers [Y.H. Yau, Application of a heat pipe heat exchanger to dehumidification enhancement in tropical HVAC systems—a baseline performance characteristics study, International Journal of Thermal Sciences 46 (2) (2007) 164–171; Y.H. Yau, The analysis of enthalpy change with and without a heat pipe heat exchanger in a tropical air conditioning system, International Journal of Energy Research 30 (15) (2006) 1251–1263], two series of experiments were conducted under controlled conditions to establish the baseline performance characteristics of the heat pipe heat exchanger (HPHX). In the present paper, a complete empirical transient systems simulation program model is assembled to estimate the air states as well as the entire typical meteorological year energy consumption of an operating theatre located in Kuala Lumpur, Malaysia. 相似文献
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Efficiency of energy recovery ventilator with various weathers and its energy saving performance in a residential apartment 总被引:3,自引:0,他引:3
The energy recovery ventilator (ERV) is an effective method, which can transfer heat and moisture from the exhaust air into the outdoor fresh air to save energy in buildings. Nowadays, ERV has been widely used in the commercial, industrial and residential buildings in China. Its energy saving performance depends on a lot of factors, such as the outdoor environmental conditions, the enthalpy efficiency of the exchanger, and so on. Based on the relationship among sensible heat, latent heat and enthalpy efficiency, we analyzed the weighted coefficient equations for describing the performance of ERV in different climatic zones in China. According to China weather data, enthalpy efficiency of the exchanger mainly depends on sensible heat efficiency in winter and latent heat efficiency in summer. The energy simulations of a sample apartment in a residential building were made under different operation conditions to study the performance of ERV. The energy saving performances of the ERV were studied with five different outdoor climatic conditions, the enthalpy efficiency, fan power consumption of ERV and fresh air change rate. To improve energy saving performance, better efficient enthalpy exchange material and higher effiencient fans must be explored, while reasonable fresh air change rate as well as proper operation period according to local climate should also be carefully considered. 相似文献
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In this paper, a simplified mathematical model develops to study round the year effectiveness of photovoltaic/thermal (PV/T) and earth air heat exchanger (EAHE) integrated with a greenhouse, located at IIT Delhi, India. The solar energy application through photovoltaic system and earth air heat exchanger (EAHE) for heating and cooling of a greenhouse is studied with the help of this simplified mathematical model. Calculations are done for four types of weather conditions (a, b, c and d types) in New Delhi, India. The paper compares greenhouse air temperatures when it is operated with photovoltaic/thermal (PV/T) during daytime coupled with earth air heat exchanger (EAHE) at night, with air temperatures when it is operated exclusively with photovoltaic/thermal system (PV/T) and earth air heat exchanger (EAHE), for 24 h. The results reveal that air temperature inside the greenhouse can be increased by around 7-8 °C during winter season, when the system is operated with photovoltaic (PV/T), coupled with earth air heat exchanger (EAHE) at night. From the results, it is seen that the hourly useful thermal energy generated, during daytime and night, when the system is operated with photovoltaic (PV/T) coupled with earth air heat exchanger (EAHE), is 33 MJ and 24.5 MJ, respectively. The yearly thermal energy generated by the system has been calculated to be 24728.8 kWh, while the net electrical energy savings for the year is 805.9 kWh and the annual thermal exergy energy generated is 1006.2 kWh. 相似文献
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介绍了水环热泵空调系统辅助热源的形式,提出了采用空气源和电加热作为辅助热源的空气源-水环复合热泵空调系统,研究了不同室外温度时建筑不同内外区冷热负荷比下该系统的能耗,分析了循环水温对系统能耗的影响,比较了该系统与采用电热锅炉和燃煤锅炉的传统水环热泵空调系统的一次能耗。 相似文献
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For indoor swimming pools, a lot of energy is needed to control the indoor temperature, relative humidity and pool water temperature. Meanwhile, the indoor air contains a high specific enthalpy due to water evaporation. A new heat pump dehumidifier is studied to reduce energy consumption. The most significant feature of this system is that it can not only recover the latent heat from indoor moist air, but also absorb heat from outdoor air to heat the indoor air and pool water. First, indoor environmental conditions, including space parameters and pool temperature, are analyzed based on human thermal comfort and energy saving. Subsequently, the models of heat and moisture gain are built. After that, the construction and operating modes of the heat pump dehumidifier are described, and the system model is established based on polynomial equations model. In a case study, an indoor swimming pool with a heat pump dehumidifier in Shanghai is studied. When outdoor air specific enthalpy is higher than 18.6 kJ/kg, the requirement of pool water heating can be met only by the heat pump dehumidifier, thus, auxiliary pool heater will not to be put into use. At last, economic analysis between the heat pump dehumidifier and conventional dehumidifier is conducted. 相似文献
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Energy recovery systems can be used in HVAC to reduce energy consumption by recovering wasted energy from the exhausted air to pre-cool inlet fresh air. In this paper, experimental study of utilizing cooling coil (CC) and cooling coil combined with heat exchanger (CCHE) has been developed. Considering the different climate zones in Iran, the experimental study has been done for the areas with high humidity content. In each case, the effects of air-to-air heat exchanger (HE) on the sensible and latent cooling load are investigated. The analysis gives the applicability of HE in Iran for various operational conditions to obtain air with lower moisture content. In CCHE systems more latent load quota is allocated in cooling coils and lower air humidity ratio can be obtained. Also in the cities with higher dew point depression (difference between dry-bulb and dew point temperature) more humidity reduction is achieved and the difference between latent load quotas of CCHE system is higher than CC system. 相似文献
9.
Xiaoli Hao Guoqiang Zhang Youming Chen Shenghua Zou Demetrios. J. Moschandreas 《Building and Environment》2007
Different types of heating, ventilation, and air-conditioning (HVAC) systems consume different amounts of energy yet they deliver similar levels of acceptable indoor air quality (IAQ) and thermal comfort. It is desirable to provide buildings with an optimal HVAC system to create the best IAQ and thermal comfort with minimum energy consumption. In this paper, a combined system of chilled ceiling, displacement ventilation and desiccant dehumidification is designed and applied for space conditioning in a hot and humid climate. IAQ, thermal comfort, and energy saving potential of the combined system are estimated using a mathematical model of the system described in this paper. To confirm the feasibility of the combined system in a hot and humid climate, like China, and to evaluate the system performance, the mathematical model simulates an office building in Beijing and estimates IAQ, thermal comfort and energy consumption. We conclude that in comparison with a conventional all-air system the combined system saves 8.2% of total primary energy consumption in addition to achieving better IAQ and thermal comfort. Chilled ceiling, displacement ventilation and desiccant dehumidification respond consistently to cooling source demand and complement each other on indoor comfort and air quality. It is feasible to combine the three technologies for space conditioning of office building in a hot and humid climate. 相似文献
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《Energy and Buildings》2005,37(5):493-501
Thermal driven desiccant assisted air conditioning systems make use of waste heat to dehumidify humid outside air in a desiccant wheel. Within the scope of a research project, an investigation of a desiccant assisted air conditioning system was carried out, and a demonstration plant was built in an office building in Hamburg, Germany. The HVAC system consists of a small CHP-plant, a desiccant assisted ventilation system and an earth energy system (borehole heat exchangers) for cooling instead of an electric driven compression chiller. The radiant floor heating system of the building is used for cooling. In this paper, measurement results and investigations of performance, energy demand and operating costs will be presented. It was found that considerable primary energy savings can be achieved (70%) using desiccant air conditioning with borehole heat exchangers. But even if electric chiller is used, savings of 30% in primary energy can be accomplished. Starting costs for the demonstration plant were not higher than for a conventional system, but running costs could be reduced drastically. 相似文献
13.
转轮全热交换器对空调箱运行能耗的影响 总被引:1,自引:1,他引:0
以浦东图书馆新馆空调系统为例,分析了转轮全热交换器在空调节能方面的作用及其所受的影响:转轮全热交换器在水系统上大大减少了系统运行能耗,新风比以及室内外焓差越大,节能效果越明显。 相似文献
14.
The aim of this paper is to explore methods to reduce the energy consumption of a central cooling plant. To achieve this, we have developed a new design for heating, ventilating and air conditioning (HVAC) efficiency improvement. A storage tank together with an immersed heat exchanger is installed in the discharge line between the compressor and condenser. The heat exchanger uses the make-up water of the cooling tower to reduce the refrigerant temperature entering the condenser. To investigate the potential of energy savings, we used a real-world commercial building with a central cooling plant, located in a hot and dry climate, for our case study. The energy consumption and relevant data of the existing central cooling plant were acquired over the course of a typical week in summer. The integrated system has been modeled and analyzed to achieve energy conservation. The performance of the proposed cooling system was simulated using a transient simulation software package. Comparison of the proposed system with existing cooling plant is included in this paper to demonstrate the advantages of our new configuration. Results show that up to 18% power saving can be obtained by using our design. 相似文献
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Conventional heating, ventilation, and air conditioning (HVAC) systems are incapable of providing control over individual
environments or adjusting fresh air supply based on the dynamic occupancy of individual rooms in an office building. This
paper introduces the concept of distributed environmental control systems (DECS) and shows that improvement in indoor air
quality (IAQ) and energy efficiency can be achieved by providing required amounts of fresh air directly to the individual
office spaces through distributed demand controlled ventilation (DDCV). In DDCV, fresh air is provided to each micro-environment
(room or cubicle) based on input from distributed sensors (CO2, VOC, occupancy, etc.) or intelligent scheduling techniques to provide acceptable IAQ for each occupant, rather than for
groups or populations of occupants. In order to study DECS, a numerical model was developed that incorporates some of the
best available models for studying building energy consumption, indoor air flow, contaminant transport and HVAC system performance.
The developed model was applied to a DECS in a model office building equipped with a DDCV system. By implementing DECS/DDCV
and intelligent scheduling techniques it is possible to achieve an improvement in IAQ along with a reduction in annual energy
consumption compared to conventional ventilation systems. 相似文献
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提出对热、湿处理过程进行单独(火用)评价的概念,并构建了相应评价指标.以某一次回风空调系统的典型夏季空气处理过程为例,在热力学极限意义上阐明了对热、湿处理进行单独(火用)评价的实施过程,计算结果表明该空气处理过程的显热(火用)效明显高于潜热(火用)效,潜热(火用)效低下的原因主要在于再热显热(火用)损和冷凝水(火用)损... 相似文献