Hi Mr Ang,

I believe you are writing from a consultancy house ?

Heating and Cooling COP varies greatly based on application.

If you are designing based on supply of hot water to coil in AHU, we reckon that you will be using it for humidity control within hospital.

There are 2 options available. One is to use Hot & Cold Water. the 2nd one is to use refrigerant.

Attached is a simulation document.

Do let me know if we can meet, so we can explore this in greater details

We can do built in water pumps for the heat pump.

Previous attached COP does include circulation pumps.

Is your 150 RT 2 no, 1 running, 1 standby ?

Attached preliminary calculation based on 150RT, including circulation pumps ( Hot & Cold )

Min load capable is 11.3 RT

Hence, capacity control is between 11.3 RT(40 kW) - 150RT, fully automatic.

Do let me know if this selection is good, and we can work out more details.

We have a similar setup which was qualified for GreenMark Platinum project. It is installed at MapleTree Business City.

Consultant was then TYLIN, builder was Shumizhu.

This design was also recognized and awarded by Spring Singapore, for Innovation project in Singapore.

* Screenshot in attachment *

The "Small makeup water tank" I am referring to is similar to the expansion tank in chilled water system.

For the purpose of humidity control, it is not necessary to raise the temperature to 45 degC. It will be a waste of energy.

This is because the compressor now has to operate at a higher condensing temperature, which causes a drop in efficiency and capacity.

Hypothetically, if we were to raise the water temperature from 35 Deg C to 45 Deg C, using exactly the same equipment.

We would expect the following performance differences :

1. 5.85% drop in heating capacity

2. 11.1% drop in cooling capacity

3. 22% Increase in power consumption

4. COP drop from 9.3 to 7.06.

Our typical heat pump system using a similar setup, can achieve up to 18 Deg C, 35% RH room condition.

We do not need buffer tanks for this system, as the compressors are inverter driven. A small makeup water tank, approx 100L installed at highest point of pipe line to feed water into pipes would suffice.

Using HOT & COLD Water

Hot & Cold Water Design based

on HW outlet of 45C, CW outlet

of 7C

Hot & Cold Water Design based

on HW outlet of 35C, CW outlet

of 9C

description

heating capacity (kW) 500.9 532

heating capacity (RT) 142 151

cooling capacity (kW) 412.07 463

cooling capacity (RT) 117 132

Power Input Compressor (kW) 117.12 96

Power Input Pumps (Hot & Cold) 11 11

Total Power Input (kW) 107 107

Theoritical COP 7.06 9.3

24.09 % reduction in COP

with 510kw heating, air flow rate is 88.66667 m3/s = 319200

532kW

(40-35) x 1.2

with 88.7ms/s, cooling capacity is 1.2 x 88.7 x (13-9) = 425.76 kW

Hypothetically, if we were to raise the water temperature from 35 Deg C to 45 Deg C, using exactly the same equipment.

We would expect the following performance differences :

1. 5.85% drop in heating capacity

2. 11.1% drop in cooling capacity

3. 22% Increase in power consumption

4. COP drop from 9.3 to 7.06.