Optimization Of Piglet Building Envelopes Based On Dynamic Simulation And LCC

Temperature environment inside piglet houses is very important for piglets’health since the piglets have just suffered from ablactation hyperirritability and are very sensitive to low temperature. In the hot-summer and cold-winter zone of China, the pig buildings have both heating requirement in winter and cooling requirement in summer. Currently, the pig houses of this place are so poor in construction and environment control that many problems arise from cold and heat stress of pigs. Insulation of farm buildings has many advantages like improving the thermal environment, saving energy and so on; however there is little awareness of pig buildings’ insulation in the hot-summer and cold-winter zone of China. The effects of improving thermal environment, energy-saving and bringing economic benefits of different envelope optimization methods for a typical piglet building are analysed in this research, and it is of considerable theoretical value and practical significance for improving thermal environment inside piglet houses, saving energy and bringing economic benefits.The critical temperature range for piglets is defined as16～32℃, and the comfort temperature range is defined as20～28℃. The thermal environment inside the piglet house is judged by the total time when the temperature is beyond critical temperature range or comfort temperature range within the production time in a year. In this research, the thermal environment improving effect and energy-saving effect of different envelope optimization methods for a typical piglet building in Zhejiang province are analysed based on dynamic simulation software-EnergyPlus; and the economic performances of different methods are also analysed based on life cycle cost analysis. The results of this research are as follows.1) The results of comparison between simulated and measured temperate in winter heating season are:coefficient of determination R2is0.81; root-mean-square error RMSE is0.94; the maximum difference is2.14℃and the mean difference is0.76℃. The difference between simulated and recorded coal consumption in the studied winter is7.9%. The difference is acceptable and this indicates that the dynamic simulation of EnergyPlus is precise to certain extent.2) The use of insulating glass can bring some effects of improving thermal environment and saving energy; but the effects are not significant. Within the critical temperature range, it shows no economic benefit of using insulating glass while within comfort temperature range, it is of economic benefit, which indicating that it is necessary to use insulating glass if better thermal environment is required. And the roof shading in summer shows very good effects of improving thermal environment and saving energy, which will reduce23～48%of original energy consumption; moreover roof shading in summer is very cost-effective according to LCC analysis.3) The insulation of walls and roof have remarkable effects of improving thermal environment and saving energy. The roof insulation (30～56%energy consumption reduction) is better than walls insulation (14～27%energy consumption reduction); and rock wool and XPS are preferable insulation materials. The optimization methods of piglet building envelopes have better energy-saving effect in winter compared with their performances in summer. Within the critical temperature range, the insulation of ceiling are most cost-effective; the insulation of walls can bring some, not much, economic benefit due to its relatively high cost; the gas concrete is a very effective insulation material for walls. Within the comfort range, all these roof and walls insulation methods can bring economic benefits.It can be seen that there is much room for optimization of original piglet building envelopes; and it is necessary to optimize the piglet building envelopes if the comfort temperature for piglets is required.