Regarding selection of correct compressor for any specific capacity.

[Deepak Tyagi]

I am deepak tyagi from India , And I am using horizontal chest freezers ranging from 100 litter to 600 litter capacity.

But I am confused to select the accurate compressor for any specific capacity.

Like I am using 300 litter capacity chest freezer temp range +5 ~-25.

Then how I will decide How much BTU/h or how much watt compressor is needed for same.

Is there any formula to calculate the same, or how we can select any specific compressor.

I am really looking forward to your further email.

Thanks & Regards

Deepak Tyagi

[Deepak Tyagi]

Hello Dear!

I am really waiting for your kind response.

[monkey spanners]

Usually you get the same model that is already fitted to the freezer. If you can't get the same one then you get the nearest matching btu compressor from another manufacturer.

[Josip]

Hi, Deepak Tyagi :)

welcome to RE forums ...


Hello Dear!

I am really waiting for your kind response.

All of us here on RE forums are volunteers (making our daily bread on some other job) trying to help each other when we have some free time .... so you need to have some patience until you get some answer you are looking for ... sometimes answer to your question will come very soon and sometimes you need to wait a while ....

Best regards, Josip :)

[Deepak Tyagi]

Thanks a lot for your kind revert.And really you people are doing great job.

Actually I am making solar fridge so for that I need to have dc compressor which are not available in India. But I do have the horizontal chest freezer cabinet with 65 mm puf insulation. And as there are varieties in demand so I am trying to develop different models ranging from 100 litter ,200,300,400,500,600 litter.

I want to know what capacity of compressor(in BTU/h or watt) will be suitable for 100 litter ,200 litter ,300 litter,400 litter ,500 litter ,600 litter.

Dear my main issue is that how do we calculate the capacity of compressor for like 100 litter ,200 litter horizontal chest fridge cabinet etc.

How I can convince someone that I need this much BTU/H compressor for 100 litter or 200 litter.

Is there is any formula for calculating the same , So that every time I can calculate myself without trusting on compressor vendors .

I am really waiting for your valuable response.

Thanks & Regards

Deepak Tyagi.

[chemi-cool]

You have to calculate the load capacity first, refrigerat to be used and then choose the compressor capacity.

[Deepak Tyagi]

Suppose I am using 300 litter (inner volume) horizontal chest fridge.

And I can keep 200 kg distributed mass in it like ice cream, water for freezing as well as meat . And I want to drop its temperature to -25 c.

And sometime I would to use it as refrigerator for cool drinks.

And refrigerant is R -134a ,

Now how I will get to know, what capacity of compressor (btu/h or watt) will be suitable for same.

If possible please help me to explain the same. And if you need any more information feel free to ask.

I am really waiting for your valuable response.

[mikeref]

Deepak Tyagi. I have to say, Freezer capacity larger than 300 Litres is very difficult to cool beyond -15 degrees C when using a DC compressor. -20 degrees on mains supply can have any chest freezer compressor working around 14 or more hours per day. ( Depends on Ambient and freezer contents.)

Chest freezers do not have the insulation thickness needed for DC compressors. 65mm Insulation is far short of 150mm used in commercial freezers.

[Deepak Tyagi]

Thanks for your reply !

Let me tell you sir , I am using 300 litter horizontal chest fridge cabinet which is having 65 mm puf insulation.

And I have put in this around 100 litter water to freeze , And its been 4 days now it is working on -25 c and compressor is continue working from last four days.

Thanks for suggesting about insulation , I will work on it to increase the puf insulation.

Dear I only want to know how we select any dc compressor for any particular fridge cabinet like 100 liter , 200 litter etc.

What is the formula behind it to analyse the same.

And I do have the dc compressor which is working fine on 300 litter horizontal chest fridge cabinet (65 mm puf insulation) and can reach to -25C .

[Deepak Tyagi]

Hello Dear ,

I am really waiting for your valuable response.

And yes you are definitely right that 65 mm puf insulation deep chest fridge is not comfortable for -25 C.

According to my opinion these cabinets are only comfortable to -15 C.

I really agree with you , to maintain -25 C I have to increase the puf insulation if I have to use this on Solar.



Dear now please let me know how I can understand what capacity of compressor will be suitable for any specific volume of fridge cabinet in both freezer as well as refrigerator mode.

If you want you can take example from your side.

I am really waiting for your kind revert.

[sendhilkmar]

Hi Deepak,

You have to calculate the cooling load like
1. Transmission load
2. Product load
3. Infiltration (Through door opening )

Pull down time you are looking for (Say 8 hrsor 12 hrs ,etc..). If you divide the cooling load / pull down time then you would get the cooling load in KW or BTU/Hr . Now you can choose the compressor

[Deepak Tyagi]

Thanks Dear for your reply ,

By transmission load do you mean the amount of refrigerant flowing in refrigerant cycle?
If I am correct I have put 200 gm R134 -a in 300 litter cabinet which is having 30 feet length of cooling coil.

Product load I can calculate.
I have put in this 100 kg ice and is being working on -25 C.

I do not understand Infiltration (Through door opening ).

I cannot over correct you , as you are being more experienced than me.

Can you please just take any example to make me understand about this all.

I am really looking forward to your further email.

[mikeref]

There is no external load when opening a Chest Freezer lid. ( When indoors.)
If you want to make any Chest Freezer more efficient...Install an external Condenser.

[Deepak Tyagi]

Yes I agree we can install an external condenser to make it more efficient.

But my question is quite different from it.

How do we select a compressor in BTU/hr or watt for any specific litter volume of cabinet like 100 litter ,200litter.

And as before I have told you my cabinet puf insulation is 65 mm and I wanted to install a dc compressor which will work in both refrigerator as well as freezer.

My only question is compressor capacity in Btu/hr or watt for horizontal chest fridge cabinet with 65 mm puf insulation.

[Deepak Tyagi]

I am really waiting for your kind respose .

And I hope you will help me to come out from this.

[Deepak Tyagi]

Dear I am not finding any response from your side regarding about the parameters that we must have in our mind for selection of compressor capacity for any specific litter capacity of fridge.

I hope you will reply as soon as possible.

[nike123]

My only question is compressor capacity in Btu/hr or watt for horizontal chest fridge cabinet with 65 mm puf insulation.




How do we select a compressor in BTU/hr or watt for any specific litter volume of cabinet like 100 litter ,200litter.

You don’t need to calculate anything, since, from your posts, it is clear that you don’t have solid knowledge required to make that calculations. Therefore you could approach to the problem solving differently. Just find what is compressor model of similar freezer with same volume, of established manufacturer, whose products work well in your environmental conditions, and use DC compressor of same displacement (as well as all other system components)!

That way, you don’t need to invent hot water again!

[mikeref]

:) You have no problem with direct and to the point response Nike.

[nike123]

Mostly!....;)

[gesi]

Hi Deepak. Do you have any details about chest freezer like type, model, manufacturer?
Maybe this link help you http://products.danfoss.com/productrange/list/commercialcompressors/compressors-for-refrigeration/secop-reciprocating-compressors-for-danfoss/secop-direct-current-compressors/r134a-10-45v-dc/
regards

[Deepak Tyagi]

Hello everyone , thanks for your kind revert.

But for that solid knowledge only, I am asking this question again and again, and I can answer your each and every question . I know that I am having that much capabilities .

I am only asking the procedure how to do these calculations, how much hard it may be I can follow it.

Like again I can explain each and every thing to you and if possible try to provide me the procedure to calculate it.

1. I am having the horizontal chest freezer ranging from 100 litter to 500 litter and these cabinets are with 65 mm puf insulation.

2.And I am using R-134a refrigerant in it .

3. Cooling coil pipe length in which refrigerant will circulate is 30 feet and its diameter is 5mm and that pipe is made up of cooper.These measurement are of 300 litter horizontal chest freezer.

Now I think I have given enough information , if possible try to provide me the procedure to calculate the compressor capacity according to my demand.

[nike123]

For practical purposes, this is what I use to do my calculations!
https://play.google.com/store/apps/details?id=com.alfalaval.coldroomcalculator
http://www.intarcon.es/calculadora/calc_en.html
Can you inform us that this calculations, you need, are for practical application, or you are doing it as your study assignment?
If for later, than you should ask your tutor these questions.

Or you could use search function of this forum to find some answers to your qestions which are many times answered before!