Whereas, WCFC system causes air-cooling in the swine houses but at the same time, it causes an increase in humidity. This is usually acceptable in regions with hot-dry climates,but in wet regions or in hot-wet day,due to the adverse effects on indoor humidity, WCFC system cannot cool the swine houses effectively in fact.GSHP system and AC system can aviod an increase in humidity in swine houses. In addition, GSHP system does not produce PM2.5 while CFH system can produce PM2.5 in heating peroids. At present,