The knowledge representation mode and inference control strategy were analyzed according to the specialties of air-conditioning cooling/heating sources selection. The constructing idea and working procedure for knowle...The knowledge representation mode and inference control strategy were analyzed according to the specialties of air-conditioning cooling/heating sources selection. The constructing idea and working procedure for knowledge base and inference engine were proposed while the realization technique of the C language was discussed. An intelligent decision support system (IDSS) model based on such knowledge representation and inference mechanism was developed by domain engineers. The model was verified to have a small kernel and powerful capability in list processing and data driving, which was successfully used in the design of a cooling/heating sources system for a large-sized office building.展开更多
Solar energy powered organic Rankine cycle vapor compression cycle(ORC-VCC)is a good alternative to convert solar heat into a cooling effect.In this study,an ORC-VCC system driven by solar energy combined with electri...Solar energy powered organic Rankine cycle vapor compression cycle(ORC-VCC)is a good alternative to convert solar heat into a cooling effect.In this study,an ORC-VCC system driven by solar energy combined with electric motor is proposed to ensure smooth operation under the conditions that solar radiation is unstable and discontinuous,and an office building located in Guangzhou,China is selected as a case study.The results show that beam solar radiation and generation temperature have considerable effects on the system performance.There is an optimal generation temperature at which the system achieves optimum performance.Also,as a key indicator,the cooling power per square meter collector should be considered in the hybrid solar cooling system in design process.Compared to the vapor compression cooling system,the hybrid cooling system can save almost 68.23%of electricity consumption.展开更多
The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analy...The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analyzed.The test shows that making full use of the evaporative cooling "free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the energy efficiency ratio of the Unit(EER)is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the new wind ratio up to 50 percent,more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent.展开更多
Hydronic heating and cooling systems are considered the most efficient, greenest technology known to man for the efficient distribution of warmth and cooling;in other words, the ideal human comfort experience. For peo...Hydronic heating and cooling systems are considered the most efficient, greenest technology known to man for the efficient distribution of warmth and cooling;in other words, the ideal human comfort experience. For people who may not know what hydronics are, here’s the definition: Hydronics: A means of transferring the energy required for heating and cooling buildings utilizing water as the primary medium in an effort to maintain good human comfort and conserve energy resources. And while we are in definition mode, allow me to introduce a couple of other terms that are critically important. Comfort: My definition of comfort is being in a state of wellbeing, or not being aware of your surroundings. In this state, you are not hot, nor are you cold. Your sinuses are not too dry, nor is it too humid, and there is not a lot of noise in the background associated with the delivery of comfort. In short, if you have to think about your physical condition, you are probably not comfortable. Simply stated, if you are truly comfortable, you will not be thinking about it. Mean Radiant Temperature: Mean radiant temperature, or MRT for short, is one of those things that cannot (normally) be seen by the bare human eye, but is the primary dictator of excellent human comfort. By definition, MRT is the temperature of those solid items surrounding your body. When the MRT is high, human comfort is achieved with a lower air temperature. When the air temperature is high, good human comfort is achieved with a lower MRT. MRT can be seen using an infrared camera, but most people do not have access to this wonderful technology. Before I go into my dissertation, I want to quickly dispel a myth. People have been taught over the years that “heat rises.” This statement in and of itself is incorrect. Hot fluids rise. Hot air or hot water rise because of their differences in buoyancy compared to cooler surrounding fluids. Radiant energy travels in all directions, through the path of least resistance, including in a downward direction. The best explanation for comparison purposes is to think of being outside on a cool winter day when the sun is shining brightly and you are standing next to a dark colored wall. Your body can sense the radiant energy surrounding your body, and your body feels warmer than it really is due to this exposure to a higher MRT. Another prime example is sitting next to a campfire on a clear starlit night. Even though the ambient air temperature is low, your body can feel the radiation coming from the fire, and it feels warm and comforting on the side that is facing the fire. Your backside that is not facing the fire feels much cooler than the side that is facing the fire, so we rotate in an effort to even out this radiant exposure. If radiant energy only traveled upward, as in “heat rises,” we would have to stand on top of the sun in order to realize any comfort due to radiant energy. As was already proved in our previous statement about MRT, such is not the case. Controlling heat loss from our bodies by manipulating the MRT will guarantee that most people will be comfortable under all conditions. As can be seen from the above graphic, radiational losses account for nearly half of the human body’s heat loss.展开更多
Evaporative cooling(EC)is an ancient technique that is usually suitable for hot and dry climatic conditions due to the potential of water vapor evaporation.In this study,three kinds of evaporative cooling systems such...Evaporative cooling(EC)is an ancient technique that is usually suitable for hot and dry climatic conditions due to the potential of water vapor evaporation.In this study,three kinds of evaporative cooling systems such as direct EC(DEC),indirect EC(IEC),and Maisotsenko cycle EC(MEC)were locally developed at lab-scale.The performance of the systems was evaluated and compared for agricultural storage and livestock air-conditioning application in Pakistan.The experiments were performed for climatic conditions of Multan city(Pakistan)and the data were collected for hourly and daily basis.According to the results,it was observed that the DEC system has the ability to reduce the temperature of ambient air to an average of 8.5℃.Whilst IEC and MEC systems were able to drop the temperature of ambient air to an average of 6.8℃and 8.9℃,respectively.As per the results,the DEC system remained behind to provide desired conditions for livestock and agricultural product storage applications due to excessive humidity.On the other hand,the IEC and MEC systems can achieve the desired conditions for livestock application,but could not provide feasible conditions for various fruits and vegetable storage.The study concludes that hybrid EC systems can be developed to provide desired conditions for a wide range of applications under varying climatic conditions.展开更多
This article presents an innovative facade system designed to increase the thermal comfort inside an office room and to enhance the cooling capacity of the suspended cooling ceiling. A series of measurements is conduc...This article presents an innovative facade system designed to increase the thermal comfort inside an office room and to enhance the cooling capacity of the suspended cooling ceiling. A series of measurements is conducted in an existing office building with different facade systems （i.e., a combination of grazing and shading）. An innovative facade system is devetoped based on this intensive set of measurements. The new system enhances the thermal comfort and cooling capacity of the suspended cooling ceiling. The main usage of the new system is the refurbishment and improvement of existing facade systems.展开更多
文摘The knowledge representation mode and inference control strategy were analyzed according to the specialties of air-conditioning cooling/heating sources selection. The constructing idea and working procedure for knowledge base and inference engine were proposed while the realization technique of the C language was discussed. An intelligent decision support system (IDSS) model based on such knowledge representation and inference mechanism was developed by domain engineers. The model was verified to have a small kernel and powerful capability in list processing and data driving, which was successfully used in the design of a cooling/heating sources system for a large-sized office building.
基金This work was supported by the National Key Research and Development Program of China(No.2017YFB0903201)the Science and Technology Project of China Southern Power Grid(No.GDKJXM20172171).
文摘Solar energy powered organic Rankine cycle vapor compression cycle(ORC-VCC)is a good alternative to convert solar heat into a cooling effect.In this study,an ORC-VCC system driven by solar energy combined with electric motor is proposed to ensure smooth operation under the conditions that solar radiation is unstable and discontinuous,and an office building located in Guangzhou,China is selected as a case study.The results show that beam solar radiation and generation temperature have considerable effects on the system performance.There is an optimal generation temperature at which the system achieves optimum performance.Also,as a key indicator,the cooling power per square meter collector should be considered in the hybrid solar cooling system in design process.Compared to the vapor compression cooling system,the hybrid cooling system can save almost 68.23%of electricity consumption.
基金Xi'an Polytechnic University Graduate Innovational Foundation(chx080608)
文摘The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analyzed.The test shows that making full use of the evaporative cooling "free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the energy efficiency ratio of the Unit(EER)is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the new wind ratio up to 50 percent,more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent.
文摘Hydronic heating and cooling systems are considered the most efficient, greenest technology known to man for the efficient distribution of warmth and cooling;in other words, the ideal human comfort experience. For people who may not know what hydronics are, here’s the definition: Hydronics: A means of transferring the energy required for heating and cooling buildings utilizing water as the primary medium in an effort to maintain good human comfort and conserve energy resources. And while we are in definition mode, allow me to introduce a couple of other terms that are critically important. Comfort: My definition of comfort is being in a state of wellbeing, or not being aware of your surroundings. In this state, you are not hot, nor are you cold. Your sinuses are not too dry, nor is it too humid, and there is not a lot of noise in the background associated with the delivery of comfort. In short, if you have to think about your physical condition, you are probably not comfortable. Simply stated, if you are truly comfortable, you will not be thinking about it. Mean Radiant Temperature: Mean radiant temperature, or MRT for short, is one of those things that cannot (normally) be seen by the bare human eye, but is the primary dictator of excellent human comfort. By definition, MRT is the temperature of those solid items surrounding your body. When the MRT is high, human comfort is achieved with a lower air temperature. When the air temperature is high, good human comfort is achieved with a lower MRT. MRT can be seen using an infrared camera, but most people do not have access to this wonderful technology. Before I go into my dissertation, I want to quickly dispel a myth. People have been taught over the years that “heat rises.” This statement in and of itself is incorrect. Hot fluids rise. Hot air or hot water rise because of their differences in buoyancy compared to cooler surrounding fluids. Radiant energy travels in all directions, through the path of least resistance, including in a downward direction. The best explanation for comparison purposes is to think of being outside on a cool winter day when the sun is shining brightly and you are standing next to a dark colored wall. Your body can sense the radiant energy surrounding your body, and your body feels warmer than it really is due to this exposure to a higher MRT. Another prime example is sitting next to a campfire on a clear starlit night. Even though the ambient air temperature is low, your body can feel the radiation coming from the fire, and it feels warm and comforting on the side that is facing the fire. Your backside that is not facing the fire feels much cooler than the side that is facing the fire, so we rotate in an effort to even out this radiant exposure. If radiant energy only traveled upward, as in “heat rises,” we would have to stand on top of the sun in order to realize any comfort due to radiant energy. As was already proved in our previous statement about MRT, such is not the case. Controlling heat loss from our bodies by manipulating the MRT will guarantee that most people will be comfortable under all conditions. As can be seen from the above graphic, radiational losses account for nearly half of the human body’s heat loss.
基金funded by Bahauddin Zakariya University,Multan,Pakistan under the Director Research/ORIC grant entitled“Development and performance evaluation of prototypes of direct and indirect evaporative cooling-based air-conditioning systems”。
文摘Evaporative cooling(EC)is an ancient technique that is usually suitable for hot and dry climatic conditions due to the potential of water vapor evaporation.In this study,three kinds of evaporative cooling systems such as direct EC(DEC),indirect EC(IEC),and Maisotsenko cycle EC(MEC)were locally developed at lab-scale.The performance of the systems was evaluated and compared for agricultural storage and livestock air-conditioning application in Pakistan.The experiments were performed for climatic conditions of Multan city(Pakistan)and the data were collected for hourly and daily basis.According to the results,it was observed that the DEC system has the ability to reduce the temperature of ambient air to an average of 8.5℃.Whilst IEC and MEC systems were able to drop the temperature of ambient air to an average of 6.8℃and 8.9℃,respectively.As per the results,the DEC system remained behind to provide desired conditions for livestock and agricultural product storage applications due to excessive humidity.On the other hand,the IEC and MEC systems can achieve the desired conditions for livestock application,but could not provide feasible conditions for various fruits and vegetable storage.The study concludes that hybrid EC systems can be developed to provide desired conditions for a wide range of applications under varying climatic conditions.
文摘This article presents an innovative facade system designed to increase the thermal comfort inside an office room and to enhance the cooling capacity of the suspended cooling ceiling. A series of measurements is conducted in an existing office building with different facade systems （i.e., a combination of grazing and shading）. An innovative facade system is devetoped based on this intensive set of measurements. The new system enhances the thermal comfort and cooling capacity of the suspended cooling ceiling. The main usage of the new system is the refurbishment and improvement of existing facade systems.
