One of the new methods for ensuring that the battery in a thermal energy storage system is kept at the proper temperature is the heat pipe-based ThermalManagement System(TMS).In this study,the improvement of cooling p...One of the new methods for ensuring that the battery in a thermal energy storage system is kept at the proper temperature is the heat pipe-based ThermalManagement System(TMS).In this study,the improvement of cooling performance of a heat pipe based TMS is examined through the variation of condenser section length of heat pipes in an array.The TMSs with an array of heat pipes with different condenser section lengths are considered.The system performances are evaluated using a validated numerical method.The results show that a heat pipebased TMS provides the best cooling performance when a wavy-like variation is employed and when the condenser section length of the last set of the heat pipe in the array is greater than that of the penultimate set.The maximum cell temperature and the maximum temperature difference within the cell of this TMS are decreased by 4.2 K and 1.1 K,respectively,when compared to the typical heat pipe based TMS with zero variation in its condenser section length.Conclusively,the strategy offers an improvement in the thermal uniformity for all the TMS cases.展开更多
The air conditioning system in the Umm Al-Qura University (Albdiya Campus) was conceived to be a district cooling by a remote chilled water plant. Recently, there are two chilled water plants in the university install...The air conditioning system in the Umm Al-Qura University (Albdiya Campus) was conceived to be a district cooling by a remote chilled water plant. Recently, there are two chilled water plants in the university installed strategically to provide chilled water to all the academic and administrative buildings of the university through distribution network with total capacity approximately of 12,000 tons of refrigeration. The plants were built based on cooling towers with open water cycle as heat rejection system. Water treatment chemicals has been used to protect the cooling systems from corrosion, scaling and microbiological fouling accompanied with dissolved and suspended water impurities. Different methods are being used to determine and control the treatment chemical concentrations and system performance indicators. Traditional chemical controller has drawback of indirect measurements and set points. The purpose of this paper is to present a solution to overcome the problems of traditional and conventional chemical treatment and control sys-tems. Central cooling plant number (1) assigned to perform experimental setup using new chemical treatment technology. Advanced automatic chemical treatment controller installed on condensers (1, 2 and 3), and certain key performance indicators were selected and monitored such as chemical and water consumption, power, energy saving, and maintaining system integrity and efficiency. Satisfactory results were obtained in terms of performance and cost of operation.展开更多
The operating theory of an evaporative condenser was expatiated.The difference between an evaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and th...The operating theory of an evaporative condenser was expatiated.The difference between an evaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative condensers were analyzed.Some questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative condensing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.展开更多
This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,an...This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,and the test requirements were presented.It proves that the load ratio of chiller has big influence on the test result,and the best load ratio for test is the range of 80%～100%.A case has been executed to validate the model's feasibility.展开更多
The choked back pressure characteristic of the steam turbine unit with air cooled condenser is very different with the unit with wet cooling technology, and the understanding of the choked back pressure performance ch...The choked back pressure characteristic of the steam turbine unit with air cooled condenser is very different with the unit with wet cooling technology, and the understanding of the choked back pressure performance change with operation load is important to guide the economic operation of the unit. One simplified Variable Operation Condition Analysis Method was put forward for calculation of the unit output-turbine back pressure characteristics. Based on this method, the choked back pressure for each operation load can be determined. An example was given for a super-critical, regenerative single-shaft, 2-casing with 2-exhaust steam turbine generation unit with air cooled condenser. The calculation result was provided and compared with the result of the unit with wet cooling technology.展开更多
Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions a...Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.展开更多
文摘One of the new methods for ensuring that the battery in a thermal energy storage system is kept at the proper temperature is the heat pipe-based ThermalManagement System(TMS).In this study,the improvement of cooling performance of a heat pipe based TMS is examined through the variation of condenser section length of heat pipes in an array.The TMSs with an array of heat pipes with different condenser section lengths are considered.The system performances are evaluated using a validated numerical method.The results show that a heat pipebased TMS provides the best cooling performance when a wavy-like variation is employed and when the condenser section length of the last set of the heat pipe in the array is greater than that of the penultimate set.The maximum cell temperature and the maximum temperature difference within the cell of this TMS are decreased by 4.2 K and 1.1 K,respectively,when compared to the typical heat pipe based TMS with zero variation in its condenser section length.Conclusively,the strategy offers an improvement in the thermal uniformity for all the TMS cases.
文摘The air conditioning system in the Umm Al-Qura University (Albdiya Campus) was conceived to be a district cooling by a remote chilled water plant. Recently, there are two chilled water plants in the university installed strategically to provide chilled water to all the academic and administrative buildings of the university through distribution network with total capacity approximately of 12,000 tons of refrigeration. The plants were built based on cooling towers with open water cycle as heat rejection system. Water treatment chemicals has been used to protect the cooling systems from corrosion, scaling and microbiological fouling accompanied with dissolved and suspended water impurities. Different methods are being used to determine and control the treatment chemical concentrations and system performance indicators. Traditional chemical controller has drawback of indirect measurements and set points. The purpose of this paper is to present a solution to overcome the problems of traditional and conventional chemical treatment and control sys-tems. Central cooling plant number (1) assigned to perform experimental setup using new chemical treatment technology. Advanced automatic chemical treatment controller installed on condensers (1, 2 and 3), and certain key performance indicators were selected and monitored such as chemical and water consumption, power, energy saving, and maintaining system integrity and efficiency. Satisfactory results were obtained in terms of performance and cost of operation.
基金Supported by the combined project of the Science and Technology Ministry of Guangdong province and the Science and Tech-nology Ministry of Guangzhou city(2007A04020004,2007C13G0161)
文摘The operating theory of an evaporative condenser was expatiated.The difference between an evaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative condensers were analyzed.Some questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative condensing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.
基金Supported by National Key Technologies R&D Program(2006BAJ02A10)
文摘This paper established an on-line monitoring model for fouling resistance of cooling water based on heat transfer theory,which was mainly applied to the fouling resistance test for condenser of chiller in operation,and the test requirements were presented.It proves that the load ratio of chiller has big influence on the test result,and the best load ratio for test is the range of 80%～100%.A case has been executed to validate the model's feasibility.
文摘The choked back pressure characteristic of the steam turbine unit with air cooled condenser is very different with the unit with wet cooling technology, and the understanding of the choked back pressure performance change with operation load is important to guide the economic operation of the unit. One simplified Variable Operation Condition Analysis Method was put forward for calculation of the unit output-turbine back pressure characteristics. Based on this method, the choked back pressure for each operation load can be determined. An example was given for a super-critical, regenerative single-shaft, 2-casing with 2-exhaust steam turbine generation unit with air cooled condenser. The calculation result was provided and compared with the result of the unit with wet cooling technology.
文摘Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.
