The Design And Analysis Of A Zoning Air-Conditioner By Peltier Heating And Cooling

According to Peltier theory, if an electric current flows in a circuitmade of N type and P type semiconductor module, the connection of twomodules can generate heat or cool. The air-condition which utilizes Peltieris named as semiconductor air-condition. Semiconductor refrigeration isa mature technology, which are commonly employed in submarineair-condition (AC), militaryennrionement controller, and automotive AC.Although semiconductor refrigeration has been applied widely, it seldomappears in application of residential AC. Utilizing semiconductor heatingand cooling technology, a novel zoning AC in bed, namely bed AC, wasdeveloped. The bed AC has following features:(1) The size of bed AC is2m high×1.5m width×2.2m length. The material of canopy is kind of tightknit fabric, and is designed to maintain local temperature of sleep space at22oC for winter and28oC for summer.(2) The bed AC equips a cool uniton the head block and heat unit on the feet block. The supply air rate arecorrespondingly1m~3/min and2m~3/min. Using calculation, it is reasonableto use two XHX585heat sinks for heat unit and cool unit. In the summerwhen room temperature is lower than30oC, bed AC can decrease bedtemperature to28oC. When room temperature is higher than30oC, bed ACshould cooperate with room AC to decrease bed temperature to28oC. Inthe whole winter, bed AC can satisfy the whole winter heating demand.The research of this paper is focused on bed AC charaters of the electicialconsumption and “cool head and warm feet”.Bed AC and room AC are operated at two same size and neighboringrooms to compare their performance on energy consumption. Room AC is to maintain the whole room temperature around28oC in summer and22oCin winter. While bed AC only needs to hold bed temperature at the samelevel with that of room AC. Comparing the energy consumption of bed ACand room AC, the energy comsumption charcater of bed AC can be find.At head, waist and feet region of bed, temperature measuring points werearranged to collect the average temperature of the three regions. Accordingto these temperature data, the “cool head and warm feet” charcater is clear.Mathematical model of bed AC electrical consumption is also built. Usingthis mathematical model, a TRNSYS bed AC type is worked out. Bypluging the bed AC type into TRYSYS simulation system, a couplingsimulation of room AC and bed AC can run under Shanghai weather. Sothe annual energy saving of bed AC can be obtained.The experimental results can be summarized as two aspects.(1) Theoperating of Bed AC satisfies heating demand during the whole winter andcan save85%of electricity consumption compared with that of room AC.Bed AC can decrease bed temperature to28oC when room temperature islower than30oC, and can save90%of electricity consumption. Whenroom temperature is higher than30oC, bed AC should cooperate withroom AC to decrease bed temperature, and only save9%of electricitycomparing with that room AC.(2) Feet region air temperature was4oC to6oC higher than head region air temperature when heat unit worked inwinter, and was about1oC higher when cool unit worked in summer. So itimplies that the effect of “cool head and warm feet” is obvious in winter,and weak in summer.(3)The relative error of electical consumption of bedAC between the calculation results and the experimental results is in±20%.The sumulatoin results can summaried as following two aspects:(1)Compared with the conventional room AC, bed AC can save43%and13%of electricity consumption in normal room, correspondingly in winter andsummer. While in energy saving room, it can save39%and7.5%respectively.(2) For enhancing energy saving rate during the summer, bedAC was redesigned for air supply and return style in summer, which was that the air supply duck was located at the top of bed AC, and the air returnduck was still placed head region. In this way, air supply vent was far awayfrom head, so bed AC can increase the cooling output to satisfy the wholesummer. The results from TRNSYS simulation show that the bed AC cansave45%and38%of electricity in summer, respectively in normal roomand energy saving room.