ESCO Air Conditioning Practice Exam

If 10 pounds of refrigerant pass through a water-cooled condenser losing 20 BTUs of heat per pound, and 10 pounds of water enter at 80°F, what is the temperature of the water leaving the condenser?

1. 90°F

2. 95°F

3. 100°F

4. 105°F

The correct answer is: 90°F

In this scenario, we are dealing with a water-cooled condenser that is removing heat from the refrigerant passing through it. Since each pound of refrigerant loses 20 BTUs of heat, and there are 10 pounds of refrigerant passing through, the total amount of heat removed from the water-cooled condenser is 10 pounds * 20 BTUs/pound = 200 BTUs. To determine the temperature of the water leaving the condenser, we need to consider the specific heat capacity of water, which is 1 BTU/(lb °F). This means that 1 BTU of heat is required to raise the temperature of 1 pound of water by 1°F. Given that 10 pounds of water enter the condenser at 80°F and 200 BTUs of heat are removed, the temperature increase of the water leaving the condenser can be calculated as 200 BTUs / (10 pounds * 1 BTU/°F) = 20°F. Therefore, the temperature of the water leaving the condenser would be 80°F + 20°F = 100°F. Thus, the correct answer is C.