详情

原文传递 ENTHALPY AND HVAC: VISUALIZING ENERGY MOVEMENT

题名：	ENTHALPY AND HVAC: VISUALIZING ENERGY MOVEMENT
正文语种：	eng
作者：	JIM COKONIS
作者单位：	Carquest Technical Institute and Advance Professional
摘要：	An accurate refrigerant charge provides the most efficient operation in a normal system and promotes lubricant flow. Even slightly undercharged systems can suffer from a lack of lubrication. Reduced system capacities in newer vehicles have made charge accuracy more critical to proper operation, and it's crucial we as technicians get it right.There are manufacturer-specific performance tests that are made for specific make, model, and year applications. These are found in service information and are designed to help place the vehicle and system in a specific state. Only then can the performance of the system be measured accurately under the conditions present. Examples of vehicle conditioning may specify if the vehicle is in the sun or the shade. Are the doors or windows open or closed and by how much? The system settings are specified and allowed to stabilize under those conditions. Then the temperatures and pressures are measured and compared to published specifications based on ambient temperature and humidity levels. Again, this test is platform-specific and based on system design, volume, and refrigerant. There is no generic HVAC system performance test that fits all. There are less precise tests like "temperature difference between ambient and vent," with a goal of a specific drop. These may not be as accurate an assessment of a system as the manufacturer-specific performance test.
出版年：	2021
期刊名称：	Motor age
卷：	140
期：	5