chảy máu một số nước lưu thông để ngăn chặn một nồng độ vượt quá khoáng sản trong nước. Để kết hợp này xuất huyết với hoạt động của máy bơm hạn chế sự mất nước trong quá trình hoạt động. Điều khiển | 26 Evaporative Air-Conditioning Applications for Environmentally Friendly Cooling Figure . Common Cabinets for Residential Coolers in India Photo R. Foster. bleeding off some of the water circulated to prevent an excess concentration of minerals in the water. To combine this bleeding off with operation of the pump limits the loss of water during operation only. Controls Direct-drip air-conditioners can generally be run on two speeds with or without the pump. Operating the air-conditioner without the pump can be desirable when the outside humidity is too high for effective cooling but ventilation still provides some comfort. In the United States and Australia many EACs are now also supplied with an indoor thermostatic control to stop the unit when it gets too cold and start it when it gets too hot. The aứ outlet of either the air-conditioner or the duct is usually fitted with a bidữectional set of louvers to control the direction of the airflow. Indirect-Direct Evaporative Air-Conditioning A two stage aừ-conditioner combining indirect and direct processes is gaining popularity in the United States in places where the higher wet-bulb temperatures . higher ambient humidity does not permit sufficiently low indoor temperatures from a simple direct air-conditioner. In this system the outside air is precooled in an indừect stage and then further cooled in a subsequent direct stage. The first stage cools the air without adding moisture and in the second stage moisture is added. The result is that the final air temperature leaving the aứ-conditioner is generally C lower than what could be achieved with a direct aữ-conditioner only. This expands the application of evaporative air-conditioning considerably to areas with slightly higher wet-bulb temperatures. Commonly 65 percent indừect stage efficiency performance factor is reached which allows an ambient wet-bulb temperature of up to 25 c to provide low enough room temperature for real comfort see Figures and .
