HEX Thermal efficiency with supply sensor

File: HEX Efficiency Supply.doc

Last edition: 2003-03-04

Author: Mikael Krantz

History: 96-02-14/MK First released version.

96-09-30/MK Updated to Menta 1.20
Alarm block has new name and text.
Pri added on alarms.

97-08-27/MK Updated to Menta 3.0

98-12-21/MK New filename

2003-03-04/MK Updated to Menta 4.0

Description

t2 - t1

Formula: -------

t3 - t1

where t1 = Supply temperature before HEX.
t2 = Supply temperature after HEX
t3 = Return temperature before HEX
t4 = return temperature after HEX

Efficiency calculation for Heat exchanger with use of an supply air temperature sensor placed after the heat exchanger. The efficiency is calculated as a value between 0 and 100%. An alarm is set if the efficiency is to low while the HEX control is above a set limit. If the numerator or the denominator are below 2°C, or if the running signal is false, the calculation output is zero, and the alarm interlocked.

Inputs

(Real) Inlet temperature

(Real) Outlet temperature

(Real) Outdoor temperature

(Real) HEX Control signal, 0-100%.

(Binary) Running signal

Outputs

(Real) Thermal efficiency 0-100%

(Binary) Low alarm thermal efficiency

Parameters

(Real) EfficiencyLimit 40%

(Real) HEXControlLimit 90%

Public signals

(Real) EfficiencyLimit

(Real) HEXEfficiency

(Real) HEXControlLimit

(Binary) HEXAlarm

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