Friga Bohn correction factors

[Andy W]

Does any one have the correction factors for a Friga Bohn MUC420 using R134a gas evaporating at -6oC as the book only shows R404a, I need to check the duty on one I fitted earlier today, not convinced it is matched to the existing condensing unit.

[Peter_1]

IS this usefull?

[Samarjit Sen]

Dear Andy W,

The literature of MUC does not intimate any thing about the application range of 134a. However if you can intimate to me the capacity of the unit required and the condensing temp as you have already intimated the required temperature and the model, I may assist you to get the rated capacity with R 134a. I presume that the room temperature will be 0 Deg. C. If otherwise, please intimate the Room temperature.

With best wishes, Samarjit Sen

[Samarjit Sen]

Dear Andy W,

The correction factor for 134a from R 404a as per Friga Bohn is 0.91. If you want further details or the pdf documents on this and the MUC series please contact me and let me know as to how can I attach the relevant documents. I am not much of an expert on computer operating.

[Samarjit Sen]

Andy W,

Pls. find the relevant document. I hope this serves your purpose.

[Peter_1]

As already stated in the header of post 2 Samarjit Sen

May I ask, why you named the document Evapo.gb.pdf?

I ask you this because Evapo Belgium was long time the sole importer of Friga Bohn since ECR bought Evapo and they were integrated in the European ECR group.

[Samarjit Sen]

Hi Peter 1,

This is the name given in the Friga Bohn documents. If the documents serves the requirement then why bother about the name.

With best wishes, Samarjit Sen

[Andy W]

Thanks guys, exactly what I was after, what would I do with out you all.

[Peter_1]

Hi Peter 1,

This is the name given in the Friga Bohn documents. If the documents serves the requirement then why bother about the name.

With best wishes, Samarjit Sen

Why you think i bothers me, I was just curious how this passed name suddenly came back?
That's all, especially because I first met BESC5240 at Evapo
Nostalgic feeling, you know S.S.

[Samarjit Sen]

Sorry Peter 1 if I have offended you which I did not mean to be. I shall find out why it has been named as such from Heatcraft as they are now dealing with Friga Bohn products.

With best wishes, Samarjit Sen

[Peter_1]

Sorry Peter 1 if I have offended you which I did not mean to be. I shall find out why it has been named as such from Heatcraft as they are now dealing with Friga Bohn products.

With best wishes, Samarjit Sen

Samarjit Sen, not al all, I learned via this forum that if English is not your mother tongue, then it's so difficult to express exactly what's in your mind, al last..valid for myself.

[Icefrog]

Does any one have the correction factors for a Friga Bohn MUC420 using R134a gas evaporating at -6oC as the book only shows R404a, I need to check the duty on one I fitted earlier today, not convinced it is matched to the existing condensing unit.

At minus 60°C (blood chamber I guess....) make sure that you send a low voltage in the fan motors so they act as small heaters. Otherwishe they will never start again

[Samarjit Sen]

It is minus 6 Deg. C. Further with R 134a you cannot get minus 60 C.

[SteinarN]

I find the capacity tables of evaporators in general to be very optimistic. I have got the impression that the capacity is measured in a dry environment, and then multiplied with 1,25 to simulate humid condition. However, how moist have it got to be in a cold rom for the evaporator capasity to get 25% higher?!? 150% humidity? I have learned to multiply the wanted evaporator capacity with at least 1,5 and then pick the right evaporator. And i can adjust the XV.

[GHAZ]

Hello andy bitzer uk have cd disks on friga bohn products with calculations on it , because i got one this week.

[Peter_1]

I find the capacity tables of evaporators in general to be very optimistic. I have got the impression that the capacity is measured in a dry environment, and then multiplied with 1,25 to simulate humid condition.

That's an obligation of the certification organisation Eurovent, otherwise you compare apples with pears.
The capacity of evaporators in the brochures is always less then a real life situation.
Same for compressors, they're given with O°K subcooling, so capacity is less then a real life situation where you have some degrees of SC.

[SteinarN]

That's an obligation of the certification organisation Eurovent, otherwise you compare apples with pears.
The capacity of evaporators in the brochures is always less then a real life situation.
Same for compressors, they're given with O°K subcooling, so capacity is less then a real life situation where you have some degrees of SC.

I always use softwareprogram when i calculates compressors. Also for evaporators. But still i have problems in getting the calculated evaporating capacity. Therefore i take an evaporator with 25% more capacity. Maybe the compressors has more capacity than calculated.

[Peter_1]

Well, I have then another question I will throw into this thread: if you read an evaporator capacity in the catalogue or the software gives you one, do you have to subtract additionally from this given capacity the power of the fan motors?

[nike123]

Well, I have then another question I will throw into this thread: if you read an evaporator capacity in the catalogue or the software gives you one, do you have to subtract additionally from this given capacity the power of the fan motors?

In Coolpack software Fans are box you have to fill in when you calculating cooling demand for a cold room. Also, you have module who converts evaporator capacity to catalog condition in order to be able to pick right evaporator from catalog data.

[SteinarN]

Well, I have then another question I will throw into this thread: if you read an evaporator capacity in the catalogue or the software gives you one, do you have to subtract additionally from this given capacity the power of the fan motors?

No. This capacity should be the "register" capacity, same as compressor/unit capacity - loss in suctionline. Heat from the evaporator motors is no different from other heat loads. Meaning you have to add the eveporator motors when you calculate the total heat load from lights transmission, products and so on, on the evaporator

[Peter_1]

In Coolpack software Fans are box you have to fill in when you calculating cooling demand for a cold room. Also, you have module who converts evaporator capacity to catalog condition in order to be able to pick right evaporator from catalog data.

No, not with Coolpack, the capacity given by a manufacturer, if they say that their evaporator gives 20 kW, is this then 20 kW or 20 kW minus the fan power?
Or in other words, where the fans taken in account when they gave you their capacity?

[nike123]

No, not with Coolpack, the capacity given by a manufacturer, if they say that their evaporator gives 20 kW, is this then 20 kW or 20 kW minus the fan power?
Or in other words, where the fans taken in account when they gave you their capacity?

I don't think they do that! You need to treat that as heat load.

[Samarjit Sen]

When you are assesing the Heat Load of the Room, the fan motor load has to be considered, In most of the software you will find that there is motor load. Once you assess the heat load which also includes tha fan motor load, you select an evaporator suitable for your application and based on the heat load. While selecting the Evaporator, there are factors like fin spacing, Td, and of course the refrigerant and the Te has to be provided. FrigaBohn has a very good software and so has the Helpman. Even Kuebas software is good. The software gives us a general idea and based on this we have to utillise our experience and knowledge to get a suitable Evaporator.