Mitsubishi Electronics PEH-10MYA manual Selection Procedure, Model Selection With actual examples

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SELECTION PROCEDURE

1. Model Selection (With actual examples)

First step, to select the approximate model:

Based on the cooling load and the cooling capacity listed in the capacity table, select the applicable model.

Second step, to select the model:

To select the model, the following conditions must be known:

(1)Total cooling load or sensible cooling load

(2)Indoor conditioned temperature (WB*1, DB)

(3)Designed outdoor temperature (DB)*2

(4)Designed air flow

(5)Designed external static pressure (= Wind pressure loss of air duct)*3

Notes:

*1. The correct WB is required since it has a serious effect on the capacity.

*2. The cooling capacity decreases as the outdoor temperature increases. Therefore, the estimated highest temperature during an air conditioning time frame is the "designed outdoor temperature". However, it is recommended that the abnormal outdoor temperature which may occur once or twice a year be excluded from the calculation to avoid selection of an excessively large capacity model.

*3. The wind pressure loss of an air duct should be calculated correctly. If a value having an excessive allowance is used, an excessively large model will be selected. Moreover, an excessively high air flow will be induced during actual operation causing the generation of high operating sounds and carry-over of condensed water.

(Step-1) Confirmation of operation range

Confirm that the conditions given above for the model to be selected are within the

operation range listed on Page 36.

(Step-2) Calculation of actual air flow, external static pressure, and fan motor input

Based on the designed air flow and external static pressure, obtain the actual air flow, actual external static pressure, and fan motor power input from the fan performance table for the model selected. For an explanation of how to use the fan performance table, see the following examples.

Example: PE-8MYC, 50Hz

Example 1. (To operate with values near to the designed air flow and external static pressure.)

Condition : Designed air flow 70CMM

Designed external static pressure 60Pa

Calculation : The designed point is A. Therefore, duct resistance line passing A is

dotted line.		(Pa)		Fan Performance Curve 50Hz
		450
Therefore, actual point is B for Δconnection						Recommended	Range
Actual air flow = 77CMM		400					For		connection
							operation			line
Actual external static pressure = 70Pa		350
Notes: Duct resustance line is secondary curve.		300									B
	pressure
		250					A
	static							60Pa
		200
	Total			For		connection
				operation		line
		150
		100
		50
		0
		50	55		60

Fan speed

(rpm)

1400

1300

1200

1100

1000

900

800

- 14 - Air flow (CMM)