Refrigeration unit for storeroom compartments based on air-cooled condensing unit
One refrigeration unit can provide the maintenance of temperature mode in several compartments with the same temperature. It is also possible to maintain various temperature values in several compartments with the help of one refrigeration unit. The latter variant implies that expansion pressure regulators are to be installed onto the outlet flanges of refrigerant from evaporators which boiling temperature is higher.
If several compartments are divided into groups on temperature modes, then a separate refrigeration unit can be used for each of them.
This article contains the example of storeroom compartments cooling with the help of refrigeration unit consisting of two independent systems, each of which will be able to provide maintaining of products storage conditions in its compartments group.
Main components of each refrigeration unit are: condensing unit (with condenser for air cooling of heat exchange surface), air coolers, control board, refrigerant pipelines and adjusting fittings.
Condensing units are to be installed on the open platform. The estimated value of air temperature is accepted as maximum for Southern Ukraine for the summer period of 2011 – it is 40 °С, at that the condensation temperature value is 52 °С.
The example of refrigeration unit of direct expansion, consisting of two independent systems based on condensing unit Bitzer of LH type of air cooling with semi-hermetic reciprocating compressors, is given below.
Compartment layout and main equipment location of refrigeration unit
* Data designation
* Temperature in compartment, 0С
* Output heat load, kW
Positional designations given in the drawing
1 – condensing unit of the 1st system (Bitzer LH135/4NC-20.2Y)
2 – condensing unit of the 2nd system (Bitzer LH84/4CC-6.2Y)
3, 4, 5, 6, 7 – air coolers
8 – discharge pipeline of refrigeration unit of the 1st system
9 – suction pipeline of refrigeration unit of the 1st system
10 – discharge pipeline of refrigeration unit of the 2nd system
11 – suction pipeline of refrigeration unit of the 2nd system
A – storeroom 1
B – storeroom 2
C – storeroom 3
D – storeroom 4
E – storeroom 5
F – service platform
g, h, k, n, m, p, r – shelves for products storage
Storeroom No. |
Temperature in compartment, °С |
|
1 |
-2 |
7,5 |
2 |
7,5 |
|
3 |
5,3 |
|
4 |
-5 |
5,0 |
5 |
3,8 |
Refrigerant used in refrigeration unit: R407C.
Total refrigeration capacity of compartments A B C: Q0ABC= 20.3 kW.
Total refrigeration capacity of compartments D E: Q0DE= 8.8 kW.
Condensing unit LH84/4CC-6.2Y
Type of condensing unit – with semi-hermetic reciprocating compressor and air-cooled condenser.
Structure of condensing unit, overall dimensions and connections
* 4 holes with Ø12
Condensing unit LH135/4NC-20.2Y
Type of condensing unit – with semi-hermetic reciprocating compressor and air-cooled condenser.
Structure of condensing unit, overall dimensions and connections
Positional designations given in drawings
1 – semi-hermetic reciprocating compressor
2 – air-cooled condenser
A – discharge line connection
LH84/4CC-6.2Y – ODF 1/2”
LH135/4NC-20.2Y – ODF 7/8”
LH84/4CC-6.2Y – ODF 7/8”
LH135/4NC-20.2Y – ODF 1 5/8”
C – connection of refrigerant emergency discharge valve 1 ¼-12 UNF
d – sight glasses of refrigerant level in receiver
e – sight glass of oil level in compressor crankcase
f – discharge pipeline
g – liquid refrigerant pipeline
Air coolers
Air coolers applied in this scheme, are of direct expansion, with battery forced blowing-off, and are ceiling type coolers.