Additional Information on the Proposed Methodology“Introducing heat recovery heat pumps with natural refrigerants
for the food manufacturing industries”
Default efficiency values for the reference equipment
The proposed methodology is to introduce heat recovery heat pumps (HPs) using naturalrefrigerants to the food processing industries in Thailand. The HPs can generate hot and/orchilled water used for the food processing. For the purpose of calculating the reference
emissions, this methodology introduces default efficiency values for the reference equipmentthat generates hot and chilled water.
1) Default efficiency values for the hot water supply equipment (boiler):
1.1 Survey on boilers in Thailand
According to the interviews with the major boiler suppliers Company A, B and C in Thailand,
approximately, 70% of boilers installed in Thailand is fire tube type, 15% is water tube type(inclusive of once-through type), and the remaining 15% are other types such as thermal heat
type or biomass type. It was conceived that the share of once-through boiler is still low inThailand. It was also found out that installation of economizer is not commonly conducted sincemost customers prefer to have boilers without economizer considering initial high investment
cost.
In general, oil, coal and natural gas are commonly used as a fuel of boilers in Thailand while theoil fuel boiler has the largest share among the fossil fuel boilers.
1.2 Reference boiler efficiency in Thailand
Oil and gas fire tube boiler is considered in setting the reference boiler efficiency. Coal fired
boiler is excluded with a view to securing conservativeness.
According to two major manufactures which sell fire tube boilers in Thailand, the latest
efficiency of the oil and gas fire tube boilers without economizer is 89% while the common
boiler efficiency is 80－85%. Moreover, according to Training manual on senior energy
practitioners in the field of heat set by DEDE (Department of Alternative Energy Developmentand Efficiency), the boiler efficiency in Thailand is stated as 85%.
Therefore, the reference boiler efficiency in Thailand is determined to be 89% taking the highest
value among those figures.
2) Default efficiency values for the chilled water supply equipment (compressor):
2.1 Reason for a compressor being a reference equipment and not a chiller
Unlike other industries, the food manufacturing industries operate under a wide range ofprocess temperatures (mostly within a temperature range of +120 degree Celsius to -50 degree

1Celsius). For this reason, instead of installing a chiller, a custom-made 'refrigeration system' isusually designed specifically to meet the need of a factory's operation, by combining
compressor units with condensers, evaporators and other relevant equipment.
The proposed methodology is for projects where a heat pump is introduced to reduce the inlet
water temperature to a refrigeration system at a food manufacturing plant, thereby thecompressor's cooling load is partially alleviated and its electricity consumption is reduced. Since
the refrigeration system configuration remains the same as before and the most significantly
affected by the project is the compressor's cooling load in the system, the reference equipment isidentified as the compressor.
Before the project

After the project
Heat pump
Water
at T *

Refrigeration system

Water
at T '*

Refrigeration system

To theprocess

Water
at T *To theprocess*T= Temperature*T, T'= Temperature, where T > T'Figure 1: Heat pumps and refrigeration system
2.2 Refrigerant compressor
Refrigerant compressor is a device to compress refrigerant gas. The description of refrigerant
compressor is shown in Table 1 below. There are mainly two different types: positive
displacement type and dynamic type.
Table 1: Refrigerant compressor
Refrigerant Compressor

FeatureType

Scope ofapplication

 Generates cold / hot heat by compressing the refrigerant with acompressor
 Closed circuit Possible for heating and cooling application

Positive displacement types

Dynamic typeReciprocating type, Rotary type(e.g. Screw and Scroll type)

Axial, Centrifugal typeAir coolers, chillers, refrigerators and others

2.3 Choice of compressors for the reference equipment
As shown in the Table 1 and based on an interview, the positive displacement types—
especially screw and reciprocating ones—are generally used in the food manufacturing plants in
Thailand due to their high compression ratio and low initial costs.
2

Among the positive displacement types, the scroll type is not considered in this methodology
as it is used for commercial application. Furthermore, Criterion 1 in the eligibility criteria of themethodology limits its application only to plants where the refrigeration system uses either
screw or reciprocating compressors. Therefore, the default efficiencies suitable for those twotypes are developed in this methodology.
2.4 Default COPs for compressors
The food processing industries require a large quantity of cooling heat at a wide variety ofoutlet temperature for their process, which is quite different from cooling heat required forbuildings for air conditioning application. Thai government establishes both MEPS and HEPS
for chillers used for buildings1; however, there is no standard for the compressors used in therefrigeration system for food processing. Thus, a market survey is conducted to determine thedefault COPs for the compressors.
In Thailand, there are three dominant manufacturers selling screw and reciprocating
compressors using different refrigerants to the food processing industries. After collecting
manufacturers' specifications in July 2017, COPs for individual models are levelled out using
the following conditions, and the results are summarized in Figure 2.
Condensing temperature: 38 degree CelsiusEvaporation temperature: -5 degree Celsius

COP
4.5

4.21
4.09

4.01

Company A(Screw)

4Company B(Screw)

3.5

Company C(Screw)Company A(Reciprocating)

3Company B(Reciprocating)

2.5
0200

400

600

800

1000

1200

1400

1600 kW/unit

Figure 2: COPs for screw and reciprocating compressors
Based on the above information, the default COPs for the production process in the foodprocessing industries in Thailand are set as follows:
Table 2: Default COPs for screw and reciprocating compressors
1MEPS and HEPS are for a chiller containing a compressor, condenser and evaporator all together to form a commercial
product with manufacturer's specifications, and thus different from the refrigeration system explained for the food
manufacturing industries in this methodology. For this reason, current MEPS and HEPS by Thai government is notconsidered in this methodology though MEPS and HEPS categorize the efficiency based on the types of the compressor
used in a chiller.

3Cooling
Capacity/unit (kW)COPs

50≦x<400

400≦x<800800≦x<1600

4.01

4.09

4.21

4