A Research On Radiant Heating System Coupled With Solar Hot Water And Heat Pump

Concerned the issues of building energy saving and low-carbon environment, this paper reported a research on a low temperature radiant heating system coupled solar hot water and air source heating pump (heating pump).The benefits of this system is that it can not only improve human body comfort,but also reduce energy consumption.Following research have been created out:Modeled a villa with three-storeys in Nanjing, and total floor area is 261.55m2, using hourly meteorological parameters in typical year to simulate thermal dynamic environment. Designed a capillary radiant heating system for six rooms of the villa (250m2), two type of heat sources systems are considered. A system is hybridization of coupled solar and heat pump, and another system is heat pump only.Flat-plate collector, storage tank, air pump are separately modeled.Using TRNSYS to optimize the ratio of collector area and storage tank volume (VAR). With the optimum value of VAR,analysis have been crated out to solar energy and solar collector efficiency.,and heat pump consumption by days,by months,and by years.Based on comparison of energy consumption of heat pump, compared hybridization system and heat pump only, calculated their initial investment. Experimented and analyzed single heat pump as well. Using the annual cost method to analyzed the performance of economic and energy saving of hybridization system.Following results had been created out:1) Parameters of VAR proposed innovatively for solar heating system,three steps put forward to optimize parameters of VAR:a) optimization on annual accumulate cost, b) useful heating collection and heating efficiency, c) solar heating fraction optimization. The optimum var is [0.049,0.065] with three steps simulations, which means each lm2 collector area corresponded 50-60L volume.2) Based on building energy flow simulation and heat collecting solar simulation,it was found that collector area is 48.52m2, storage tank volume is 2.75m3 according VAR being 0.057. For typical day,the useful heat from solar hot water is 525.49 MJ, the heat load 281.60MJ by heating pump, with contribution from solar collector accounted 65.11%.The annual useful solar heat is 33773.72MJ, the contribution from heating pump is 20189.71 MJ,the ratio is 8:5 between solar heating system and heating pump.3) Comparing heating energy between hybridization system and heat pump only in heating season. Heat supplied form hybridization system is 3209.25kWh,while 5753.18kWh form heat pump only,with energy saving 2543.93kWh. The extra cost of 25285 RMB from hybridization system, which can be paid back in 8 years by the energy saving.4) Considering the life cycle of 15 years,the annual-cost of hybridization system will be compared with gas-fired boiler, oil-fired boiler, electric auxiliary solar heating systems. The investment cost of hybridization system is 78,185 RMB. Which annual running cost is 1765 RMB. The annual cost is the lowest of 10,912 RMB/year. The annual energy saved standard coal of 2.30 tons and carbon emissions of 1.63 tons yearly.Three innovations have been created in this paper, using VAR parameters to solar system designing, developing three steps methods to VAR evaluation, simultaneously simulating hourly energy consumption of heat pump and building energy. The research achievements in this paper, which is a good reference for radiation system, with characteristic of high efficiency, energy saving, environmental protection.