Question : Which formula is better to use when charging an air conditioner? Please explain your answer and how you arrived at that conclusion.
Answer : This answer is for a typical air conditioner with R22 refrigerant.
Sub-cooling is how much the refrigerant is cooled below the condensing temperature of the refrigerant as it leaves the condenser coil and is typically about 15 degrees. For example if the system is running a high side pressure of 230 psi the corresponding condensing temperature would be 110 degrees. If the measured temperature of the liquid line exiting the condenser coil is 95 degrees then the sub-cool is 15 degrees.
Superheat is how much the the refrigerant is heated above its boiling point in the evaporator coil and is typically between 10 and 20 degrees. For example if the low side pressure in the evaporator coil is running at 69 psi, the corresponding boiling temperature will be 40 degrees. If the measured temperature of the suction line exiting the evaporator coil is 55 degrees, the superheat would be 15 degrees.
As far as which method is best for charging a system it depends on what type of metering devi..
Question : I just need the simple stuff. Not anything too complicated. Or a link. Links are good too.
Answer : Transpiration: Water is release through the stomata in the leaves on trees in the right conditions (I wont go into detail)
Condensation: Water droplets in warm/moist air, are cooled causing the droplets to form on windows, ect.
Evaporation: Water crystals/droplets when exposed to warm conditions, basically dry up, and are released into the air.
Question : why is evaporation important to humans and was factors affect the rate of evaporation?
Answer : Without evaporation there would be no rain and all our crops, and we, would die.
Perspiration cools by evaporation.
Evaporation depends on air and water temperature and on humidity. Air speed is also important.