COP and Refrigeration Capacity Caculation?

[Uni]

Hi all,

I'm new to RE as well as this field. However, I'm going to do the instrumentation to evaluate the COP & Refrigeration Capacity of a domestic heat pump (3kW cooling/1.5kW heating). Could someone please explain about the instrumentation & data that I need for the calculations?

I'm getting confused as I have to do all the new things in a very short time.

Thanks in advance :)

[taz24]

Hi all,

I'm new to RE as well as this field. However, I'm going to do the instrumentation to evaluate the COP & Refrigeration Capacity of a domestic heat pump (3kW cooling/1.5kW heating). Could someone please explain about the instrumentation & data that I need for the calculations?

I'm getting confused as I have to do all the new things in a very short time.

Thanks in advance :)


I dont use Wikipedia often but it may answer your questions.


http://en.wikipedia.org/wiki/Coefficient_of_performance



COP is only a ratio between energy in and energy out.
The higher the energy out for the cost of the energy in = higher COP.

Cheers taz

.

[Brian_UK]

Hi all,

I'm new to RE as well as this field. However, I'm going to do the instrumentation to evaluate the COP & Refrigeration Capacity of a domestic heat pump (3kW cooling/1.5kW heating). Could someone please explain about the instrumentation & data that I need for the calculations?

I'm getting confused as I have to do all the new things in a very short time.

Thanks in advance :)I think the COP of this unit will be a negative value ;)

[Toosh]

Hi all,

I'm new to RE as well as this field. However, I'm going to do the instrumentation to evaluate the COP & Refrigeration Capacity of a domestic heat pump (3kW cooling/1.5kW heating). Could someone please explain about the instrumentation & data that I need for the calculations?

I'm getting confused as I have to do all the new things in a very short time.

Thanks in advance :)

Hi Uni have a look at this and try searching GOOGLE its where i got this:eek:
http://www.winfridge.com/HSU-notes.html


regards Norm

[Noori]

Hi Uni
U can use temperature measurement and pressure gages to Calculate the COP and refrigerant capacity.
Noori

[Uni]

Thanks for your quick responses.

I am a student learning about instrumentation. I chopped the AC down and installed all the following stuffs:

- Wet&dry bulb thermocouples at Evaporator (Indoor) Air Inlet & Outlet
- Anemometer at the Evaporator
- Pressure transducers + thermocouples to measure all the pressures and temperatures (evap in/out, cond in/out, suction/discharge, compressor shell)
- Data logger & software
- Nothing to measure mass flow rate
:confused:

So far, I have tried the charge tuning test. This helped me a lot to gain a better understanding about the system behavior. Now I want to move on to the COP & Capacity test.


Generally said,

C.O.P.= heat transferred/electricity input

Electricity input can be measured by a Watt-meter, so I have it installed already.

1. How do we measure the heat transferred?

2. Is there any other practical method to do this?
by using wet/dry bulb evap in/out temp and air flow (cube/hour) for example
Someone used calorimeters, etc. which I do not understand.

Please everyone, be more detailed. I'm really interested in this field :)

[nike123]

2. Is there any other practical method to do this?
by using wet/dry bulb evap in/out temp and air flow (cube/hour) for example


Exactly that! You need entering air wet and dry bulb temperature (or dry bulb temperature and relative humidity) and leaving air wet and dry bulb temperature (or dry bulb temperature and relative humidity). Applying that to Mollier chart you should find enthalpy of entering and leaving air and you only need air density and air flow to calculate sensible and latent heat of that air in measure of time.
Yo could easily calculate that with numerous versions Mollier chart software or by doing your own calculations.

[Tony]

Hi Nike123,


Applying that to Mollier chart

don't you mean pschrometric chart? ;)

[nike123]

Hi Nike123,



don't you mean pschrometric chart? ;)
Sorry, I mean Mollier diagram.;)


The Mollier Diagram :
The Mollier diagram, also called the ix diagram, is based on the relationship between heat content and water vapour content of air. The heat, or energy, content is difficult to measure directly, so the diagram is cunningly distorted to give the illusion of being based on the relationship between temperature and relative humidity and water vapour content. Temperature is easy to measure, relative humidity is considered by some people to be easy to measure and so the diagram is transformed into a useful tool. The Mollier diagram is a variant of the psychrometric chart (http://www.engineeringtoolbox.com/psychrometric-chart-d_816.html). A move from the Mollier diagram to the psychrometric chart (http://www.engineeringtoolbox.com/mollier-psychrometric-chart-d_241.html) is explained here.

[Uni]

Thanks, Nike123. I will try to get it done bu the next test. :)