Heat Recovery System - Hitecsa EQU-PF 233 Manual De Instalación, Uso Y Mantenimiento

II.6.4.2 Indications for unit when operating
In this case, it is the microprocessor control board which protects the
evaporator from freezing. When the set temperature has been reached,
the antifreeze alarm is triggered stopping the unit, while the pump
keeps running normally.
The use of ethylene glycol is recommended if you do not wish to drain
the water from the hydraulic system during the winter break or if the unit
must supply chilled water at temperatures lower than 5°C (the latter
case is not considered here and depends on the size of the unit
system).
Table "H" indicates the multipliers that allow the unit performance
changes to be determined in proportion to the required percentage of
ethylene glycol.
The multipliers refer to the following conditions: condenser inlet air
temperature 35°C; chilled water temperature 7°C; temperature
differential at evaporator 5°C.
For different operating conditions, the same coefficients can be used as
their variations are negligible.
Table "H"
Minimum outdoor air temperature °C
% glycol in weight
Freezing temperature in °C
fc G
fc ∆pw
fc QF
fc P
fc QF = Cooling capacity correction factor.
fc P = Correction factor for the total absorbed electrical current.
fc ∆pw = Correction factor of the pressure drops in the evaporator.
fc G = Correction factor of the glycol water flow to the evaporator.
II.6.5

Heat recovery system

II.6.5.1 Operation
To recover the heat from the compressor and consequently produce hot
water, the differential pressure switch (PD) must give its consent to the
electronic board; to achieve this result, the circulating pump (P) must be
active and the water must circulate normally in the recovery exchanger.
The electronic board also controls the recovery unit and/or
desuperheater (ST8) outlet temperature so as to guarantee the
maximum outlet temperature.
II.6.5.2 Installation precautions
DANGER!
The recovery unit / desuperheater is set directly in
series with the compressors; therefore, the internal
temperature of the recovery exchanger can reach
120°C at a pressure of 2 bar, in particular faulty
conditions. This could lead to the formation of
steam from overheated water.
Use of anti-freeze solutions with BT accessory
The table indicates the ethylene/propylene glycol percentages to be
used in units with the BT accessory based on the produced chilled
water temperature. Contact pre-sales service for information regarding
performance of the units.
water outlet temperature
2 0 -3
10 15 20
-5 -7 -10
1,025 1,039 1,054
1,085 1,128 1,191
0,975 0,967 0,963
0,993 0,991 0,99
16
SECTION II: INSTALLATION AND MAINTENANCE
IMPORTANT!
Mixing the water with glycol modifies the
performance of the unit.
Evaporator glycol
From -3°C to -8°C
From 0°C to -2°C
From 4°C to 1°C
-6 -10
25 30
-13 -16
1,072 1,093 1,116
1,255 1,319 1,383
0,956 0,948 0,944
0,988 0,986 0,983
Minimum % glycol in
weight
30%
20%
10%
-15 -20
35 40
-20 -25
1,14
1,468
0,937
0,981