Heat Controller 60 HZR-410A Selection Procedure, Submittal Data, HBH Series, Heat Controller, Inc

Submittal Data HBH Series Heat Controller, Inc.

Selection Procedure

Step 1 Determine the actual heating and cooling loads at the desired dry bulb and wet bulb conditions.

Step 2 Obtain the following design parameters: Entering water temperature, water flow rate in GPM, air flow in CFM, water flow pressure drop and design wet and dry bulb temperatures. Air flow CFM should be between 300 and 450 CFM per ton. Unit water pressure drop should be kept as close as possible to each other to make water balancing easier. Go to the appropriate tables and find the proper indicated water flow and water temperature.

Step 3 Select a unit based on total and sensible cooling conditions. Select a unit which is closest to the actual cooling load.

Step 4 Use data from performance tables at the design water flow and water temperature. Read the total and sensible cooling capacities (Note: interpolation is permissible, extrapolation is not).

Step 5 Read the heating capacity. If it exceeds the design criteria it is acceptable. It is quite normal for Water-Source Heat Pumps to be selected on cooling capacity only since the heating output is usually greater than the cooling capacity.

Step 6 Determine the correction factors associated with the variable factors of dry bulb and wet bulb (page 14).

Corrected Total Cooling =

tabulated total cooling x wet bulb correction. Corrected Sensible Cooling =

tabulated sensible cooling x wet/dry bulb correction.

Step 7 Determine the correction factor associated with antifreeze in system loop. If heating EWT is 50°F or below you may have to use antifreeze. Calculate leaving water temperature per performance data selection notes (page 18). If antifreeze is required, use correction table for correcting total and sensible capacities.

Step 8 Compare the corrected capacities to the load requirements. Normally if the capacities are within 10% of the loads, the equipment is acceptable. It is better to undersize than oversize, as undersizing improves humidity control, reduces sound levels and extends the life of the equipment.

Step 9 When completed, calculate water temperature rise and assess the selection. If the units selected are not within 10% of the load calculations, then review what effect changing the GPM, water temperature and/or air flow and air temperature would have on the corrected capacities. If the desired capacity cannot be achieved, select the next larger or smaller unit and repeat the procedure. Remember, when in doubt, undersize slightly for best performance.

Example Equipment Selection For Cooling

Step 1 Load Determination:

Assume you have determined that the appropriate cooling load at the desired dry bulb 80°F and wet bulb 65°F conditions is as follows:

Total Cooling	90,500 BTUH
Sensible Cooling	73,300 BTUH
Entering Air Temp	80°F Dry Bulb / 65°F Wet Bulb

Step 2 Design Conditions:

Similarly, you have also obtained the following design parameters:

Entering Water Temp (Cooling)	90°F
Entering Water Temp (Heating)	60°F

Water Flow (Based upon 12°F rise in temp.)......18 GPM

Air Flow 2,800 CFM

Step 3, 4 & 5 HP Selection:

After making your preliminary selection (TCH096), we enter the data from tables at design water flow and water temperature and read Total Cooling, Sens. Cooling and Heat of Rej. capacities:

Total Cooling	93,200 BTUH
Sensible Cooling	70,390 BTUH
Heat of Rejection	120,100 BTUH
Airflow	3,200 CFM

Step 6, 7 & 8 Entering Air, Airflow and Antifreeze Corrections: Next, we determine our correction factors.

Airflow 2800 ÷ 3200 = 88%		Antifreeze - None
	Table	Ent Air Air Flow Corrected

Corrected Total Cooling = 93,200 x .977 x .976 x 1 = 88,871 Corrected Sens Cooling = 70,390 x 1.088 x .933 x 1=71,453 Corrected Heat of Rej. = 120,100 x .998 x .976 =116,983

Step 9 Water Temperature Rise Calculation & Assessment:

Rise = Heat of Reject ÷ (GPM x 500)

Actual Temperature Rise 116,983 ÷ 9,000 = 13.0°F

When we compare the Corrected Total Cooling and Corrected Sensible Cooling figures with our load requirements stated in Step 1, we discover that our selection is within +/- 10% of our sensible load requirement. Furthermore, we see that our Corrected Total Cooling figure is slightly undersized as recommended, when compared to the actual indicated load.

Alternate Step 7: If your EWT for heating is 40°F then system requires antifreeze. If a solution of 15% Propylene Glycol is required, then:

Corrected Total Cooling = 88,871 x .986 = 87,626

Corrected Sens Cooling = 71,453 x .986 = 70,452

3