# HVAC Practice Exam #1

## Practice PE Exam: HVAC Breadth and Depth

The following is a practice PE exam for the HVAC Breadth part of the PE test. I chose not to make this a multiple choice format. One the individual answer page I will show you the worked out problem and you can deride if you got the correct solution. The reason I did this is when you are looking on charts for number or multiplying by numbers that may have been rounded off your answer can vary. The way I see things is that if you can get the problem done correctly. This test should take 1 hour

#### Question 1

A mechanical room has (2) 47 kilowatt electric water heaters and (1) 3000 MBTUH natural draft gas fired boiler. You are looking to use the one permanent opening method for the combustion air opening. What area should the combustion air opening be?

#### Question 2

A water cooled chiller uses R-134a as a refrigerant. The refrigerant flow rate through the condenser is 100,000 lbm/hr with the entering pressure of 100 PSIA and leaves the condenser at a temperature of 80° F and is a saturated liquid. The refrigerant then passes through the evaporator and leaves as a gas at 10° F . Water from a cooling tower is used to absorb the heat given off by the condenser. The cooling tower water enters the condenser at 75° F and leaves at 98° F.The Coefficient of Performance for this chiller is 4.0. What is the flow rate in gpm of the cooling tower water?

#### Question 3

A client is asking to use a solar energy collector to collect energy for a solar powered pump. The solar panels have an overall efficiency of 12%. The pump will be used to pump 15 gpm of water out of a groundwater well that has been dug to a depth of 200 feet. The overall efficiency of the pump is 65%. The water that is being drawn up from the groundwater well is 80 degree Fahrenheit. The local solar radiation for the area is about 15 watts / ft^2

A pressure lose calculation on the piping is done and it is determined that the fittings will add 30 feet of head.

How much area of solar array would be required to power this pump

#### Question 4

An air handler has a 2 1/2″ diameter chilled water branch piping that supplies water to a 72″ x 48″ cooling coil that has 5/8″ copper tubes. The return air enters the coil at 100° F. The air is then cooled to 60° F. For this particular coil the maximum allowable face velocity across the cooling coil is 450 fpm. If the sensible heat ratio for this coil was given as 0.87. What is the total cooling load on the cooling coil?

#### Question 5

You have been asked to evaluate two chillers using the coefficient of performance. Both chillers are about the same tonnage and your client would like to use the more efficient chiller.

#### Chiller #1

- Flow rate of 550 GPM
- Entering Temperature 58° F
- Leaving Water Temperature 45° F
- Compressor input 25 Tons

#### Chiller #2

- Flow rate of 500 GPM
- Entering Temperature 58° F
- Leaving Water Temperature 44° F
- Compressor input 25 Tons

#### Question 6

An air handler has 15,000 cfm of air passing through the coiling coil. The velocity across the face of the cooling coil has a maximum velocity of 500 fpm. The air then passes through the fan inlet section of the air handling unit and then passes into a 18″ diameter plug fan. If a pressure sensor records a pressure of -3.0 inches immediately downstream of the cooling coil, what is the pressure when the air enters the plug fan?

#### Question 7

The design conditions for a dining room at a public school are 75° F dry bulb and 62.5° F wet bulb. Using ASHRAE 62.4 to calculate the outdoor air requirement, it was calculated that the ventilation requirement for the dining room would be 1,400 cfm. The temperature outside has a maximum range of 95° F dry bulb and 81° F wet bulb. What is the ventilation load the cooling coil will see from the outside air?

#### Question 8

A fuel depot at the airport has (3) 75 horsepower pumps that can each deliver 500 gpm of jet fuel to the holding tanks. All three pumps operate at 65% efficiency. The total dynamic head needed for each pump is 400 feet

The fuel depot is getting ready to be retrofitted. Your boss wants to know; what is the maximum throughput you can attain with the current pumps.

#### Question 9

An architect has asked you to get an estimate of the fuel that would be needed to heat an exterior wall per year. The wall has an area of 150 square feet. The thermal conductivity of the wall is 0.08 BTU/(ft^2 * h *F ). During the heating season this wall will see about 3200 degree days.

What is the total amount of heat lost in a year

#### Question 10

A 20 ton air conditioning unit has an average electrical load of 30 Kw. What is the EER rating?