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buddy
16-11-2012, 10:40 AM
Hi Guys,

Just thought I,d throw this problem at you as someone may have the answer?

The situation -
A building landlord in a shopping Mall has complained that he wants no more heat rejected into a basement car park from two air-cooled condensers serving 2 compressor racks.

However the Landlord will not allow any new equipment to be installed on his property so that excludes a cooling tower to fit water cooled condensers.

The only option I can think of is to tap into the main cooling water ring main (if there is spare capacity), and the other problem is the Air conditioning is switched off overnight where as the refrigeration system needs 24 hour cooling.

So if the option of tapping into the A/C chilled water system is a no go what options or other technologies exist out there to get us out of this fix.

Solution?

Hope you can help?

best regards

Buddy.

MikeHolm
16-11-2012, 11:43 AM
Dump the heat into a water tank for the building if he will allow it.

buddy
16-11-2012, 02:45 PM
Hi Mike,

Thank yo for your input.

I understand where you are coming from but that does not solve the problem of cooling supply water delivery to water cooled condensers that will have to be fitted.

Spencer.Guy
16-11-2012, 05:33 PM
He's done his homework and obviously wants the tennant out.
Does the Tennant have an agreement allowing them to have the basement condensers?

mad fridgie
17-11-2012, 12:53 AM
So if we can tap into the AC, but only run it during normal working hours. Why not install a tank with a phase change material. So at night, heat is rejected into the tank (being phase change, the tank is smaller). Then during the day, the AC can remove the over night heat and the day heat of rejection.
Not very efficient!

Tesla
17-11-2012, 02:34 AM
Hi Buddy
Very bad concept to reject condenser heat into a chilled water system. as stated above you could reduce the heat rejection load by heating hot water for the building - I'm sure with good communication that free hot water will be available and reduce the overall electrical load is a good start. A comprimise could be reached by removing one condenser from carpark? If you did all the calcs and could show that the ac load for the building would also reduce could be a big enough carrot. another option could be to relocate the 2 condensers to the roof and give the landlord that space back free.

buddy
17-11-2012, 02:46 AM
He's done his homework and obviously wants the tennant out.
Does the Tennant have an agreement allowing them to have the basement condensers?

Thanks Spencer,

We know that the landlords aim is get the tennent out.

He is using customers complaint for air cooled condenser removal.

When requested for specific details of the complaints (this is after over 7 years of the refrigeration condensers being in place) he has never provided one jot of information.

We know what his game plan is just wish to solve this problem technically.

Thanks for your input.

buddy
17-11-2012, 02:48 AM
So if we can tap into the AC, but only run it during normal working hours. Why not install a tank with a phase change material. So at night, heat is rejected into the tank (being phase change, the tank is smaller). Then during the day, the AC can remove the over night heat and the day heat of rejection.
Not very efficient!

Hi Mad fridge,

Sounds like a plausible idea, but would it work?

Do you have any specific examples of phase change materials?

What efficiency are they normally?

Thanks for your input.

buddy
17-11-2012, 02:52 AM
Hi Buddy
Very bad concept to reject condenser heat into a chilled water system. as stated above you could reduce the heat rejection load by heating hot water for the building - I'm sure with good communication that free hot water will be available and reduce the overall electrical load is a good start. A comprimise could be reached by removing one condenser from carpark? If you did all the calcs and could show that the ac load for the building would also reduce could be a big enough carrot. another option could be to relocate the 2 condensers to the roof and give the landlord that space back free.

Hi Tesla,

Already thought about the free hot water.

And relocating the air-cooled condensers to the roof and changing to water cooled condensers with cooling tower on the roof, the landlord wont allow it.

That is why we feel we are backed into a corner and are now scratching our heads for alternative solutions.

Thought if anybody can solve this problem you guys at refrigeration-engineer.com should be able to offer a solution.

Thanks for your input.

mad fridgie
17-11-2012, 04:06 AM
Hi Mad fridge,

Sounds like a plausible idea, but would it work?

Do you have any specific examples of phase change materials?

What efficiency are they normally?

Thanks for your input.

Technically speaking, yes it will work.

The phase change material we all know well is Ice "0C", there are many you just need to pick a working temperature for temps above "0C" normally some form of hydrated salt.
Being lazy using old fashion numbers
water 1Btu/lb/f
Ice latent heat 144BTU/lb
Most hydrated salts latent heat around 100BtU/lb

Not efficient, as you are paying twice to move the energy.

You could expand this (depending upon the type of AC), have a larger system run the AC at night, lower power rates and normally lower ambient (lower condensing), A thermal storage system.

But I think you are knackered if the the landlord whats your client out, he will do what he will to ensure he achieves his goal.

r.bartlett
17-11-2012, 09:17 AM
One for the lawyers. Get your client to have his agreement checked. I am sure he would 'win' this battle on historical and reasonable grounds. Whether he'll win the war is another matter...Plate HE on the cooling loop is the only way or duct the hot air outside (if possible etc)

hookster
17-11-2012, 10:49 AM
It would be interesting to know what the racks are cooling? i.e thermal load

Phase Change is a good option but I am guessing the surface area required for thermal storage will be large!
Then comes the requesting landlord for positioning etc!

Rob White
17-11-2012, 07:24 PM
.

I'd find out if he is on a water meter?

If not the just plumb in water cooled condensers and
waste the water down the drain. If he is not on the meter
there will be no extra cost to him. If he is on a meter,
that's different..

Rob

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