InRow Cooling Units Condenser's (Out Door Units) Comparison

[BillP]

Dear All,

I have a question regarding InRow units condensers(out door unit). As we have a range of InRow DX from 10-37kW. If we select a 30kW InRow unit with ACCD75207 (this out door unit is designed at 35 deg C) therefore, would this affect on Indoor unit efficiency? means, when the ambient temperature increases then how % of kw rating would be degraded? secondly, as we have ACCD75208 & ACCD75209 also, they both are designed at 40 & 46 deg c respectively, and also have a good price difference. but i wanna ask why we give customer generally accd75209 only bcz of higher ambient temperature or it has some other features?  why don't we give ACCD75207 because we always have N+1 Cooling redundancy in Data centers.

I will wait for your response thank u.

Thanks a lot.

Regards,

War

[BillP · Accepted solution]

Got it! Thank u so much. U are a real knowledgeable resource.

[BillP]

Dear Sir,

How r u? hope fine and doing great. I have a question, May you pls let me know that the out door units like ACCD75207, 208 and 209 can be placed on two legs so that fans face would be either left or right side, for more clarify the question,  as we know these are placed on four legs(fans facing to the sky) but if i wanna place them on two legs can i place them? if no, then pls tell me the reason.

Thanks a lot.

[BillP]

Hello. These three condensers are built for vertical airflow through them (four legs, fans facing the sky). The connections to the unit are made so the hot gas goes in the top of the condenser and the condensed liquid comes out the bottom. If these units are put on their side the connections will be in the middle instead of the top and bottom. This may cause issues in the system. The only way to see if they would work horizontally is to contact your local sales and design team. They can help you configure the solution and may be able to offer other solutions to fulfill the needs of the site.

Thank you

[BillP]

Thank u so much dear.

I'll get back to u if i have any other question.

[BillP]

Dear All,

I have a question regarding InRow units condensers(out door unit). As we have a range of InRow DX from 10-37kW. If we select a 30kW InRow unit with ACCD75207 (this out door unit is designed at 35 deg C) therefore, would this affect on Indoor unit efficiency? means, when the ambient temperature increases then how % of kw rating would be degraded? secondly, as we have ACCD75208 & ACCD75209 also, they both are designed at 40 & 46 deg c respectively, and also have a good price difference. but i wanna ask why we give customer generally accd75209 only bcz of higher ambient temperature or it has some other features?  why don't we give ACCD75207 because we always have N+1 Cooling redundancy in Data centers.

I will wait for your response thank u.

Thanks a lot.

Regards,

War

[BillP]

Hello.

     The condensers should be measured on the rating of the heat rejection and the ambient temperature that they are normally subject to. The higher the ambient temperature, the larger the condensing surface will be. This equates to a lager coil and more fans on the unit. As the ambient temperature rises, we need a larger surface to reject the heat from the refrigerant. If the surface area it too small then we will not be able to get rid of enough heat and the unit will go into high head pressure during the summer. Over-sizing the coil will waste money and could potentially cause issues if it gets to cold in the winter. The condenser should be sized to be able to reject the heat during the peak temperatures in a expected summer but not over-sized so the money is wasted. An undersized condenser will greatly reduce the capacity of the unit inside during the summer and can cause high head pressures which will shut down the cooling completely.

Thank you   

[BillP]

Dear L2,

Thanks for the provided very good info. One question I have, i.e. What is the 'Derate Factor' with respect to rising the temperature. Means, If we select ACRP102, with ACCD75207 that is designed at 35 deg.C, rated at 33kW. So, If the ambient temperature rises upto 40 deg C, in peak summer months, so how much these units would be derated? Means, from 33kW to ------??? Because, I am thinking that if one data center is running at 45kW total load. We place 3 units of ACRP with ACCD75207, So, the two cooling units which are running gives almost 60kW, If both are derated in summer season upto 5/5 kW so but still we would have 50kW, which is OK to cool down 45kW, and also we are having one other unit as standby. What do u say? This question is just for understanding. U see we have to know the 'derate factor' for clear picture. Because if derate factor is not much higher, then at least I would like to always go with ACCD75207 (if ambient temp is under control), due to compact size and lower price.

Waiting for your ever green support.

Thanks,

War

[BillP]

Hello.

The capacity rating on the condensers depends on the temperature differential (TD) between the condensing temperature and the ambient temperature. The condensing temperature of R407C is 48.8 C. So in this case the TD = 48.8 - 40 = 8.8 degrees C. The ACCD75207 will remove 4.8kw of heat per 1 degree C. This means it will remove 4.8 x 8.8 = 42.24 kw of heat. If the ambient temp raises to 45 degree C then TD = 48.8 - 45 = 3.8 x 4.8kw/1c = 18.24 Kw. This does drop of steeply as the ambient temperature rises. The ACCD75208 will remove 8.1kw per 1 degree C, while the ACCD75209 will remove 11kw per degree C. The condensing temperature is the same on all the condenser. If this need more explanation please let us know.

Thank you

[BillP]

WOW SIR...... Amazinggggg..... Detailed, neat & clean and right on target explanation. You taught me just like a teacher, a good one.

Only one thing is still confusing, i.e. U said " This means it will remove 4.8 x 8.8 = 42.24 kw", But in the file (pls download from below link) at page no. 28, under the heading of air cooled performance calculation, at 33 °C it gives 33.7kW. That is why i couldn't understand that how it would give 42.24kW.  Secondly plz see page no. 35, Under the heading of 'Mechanical Data', ACCD75207 shows, kW/°C TD is 9.3kW. What does it mean? i couldn't understand?? Same question is for ACCD75208 and 209 respectively.

https://app.box.com/s/qw5cn2fk5c22dwnwpiio

I will wait for your response. Thank  you.

Regards,

War