Residential Package unit and Chiller speculation

[motoguy128]

I was just trying to run some numbers of my own and I was wondering how you can up with your 2,500 mark. The last thing I have run across is this from ASHRAE.

All in all I'm coming up with some pretty broad numbers and I was wanting to nail something down.

That's a good question. I assume you'd have to know your average heat gain during design conditions. Then you determine what the 24 hour average is and then size your storage so your chiller is sized for hte average load and run continously but you have enough water storage.

Its' just thermal mass. You can accomplish a similar effect if you had enough concrete or masonry walls in a home. This is why IMO, energy efficient structure design needs ot encorporate materials when possible with a lot of thermal mass. SO using ICF's. I've mentioned in another thread, that I think you could easily raise the sill plate up to at least a point level with the bottom of the 1st floor windows. Homes should be 2 story and use stucco, brick or stone on the exterior. Have deep overhangs for shading the building in the summer, and less in the winter, use interior walls (non of this open concept garbage) and use stone, brick or plaster, instead of gypsum for interior walls too. Close cell spray foam of course and unvented attics with cool roofs.

Actually, with enough thermal mass in the structure, the need for water storage could then be sized to target a minimum cycle time at low load conditions.

[CraziFuzzy]

I was just trying to run some numbers of my own and I was wondering how you can up with your 2,500 mark. The last thing I have run across is this from ASHRAE.

All in all I'm coming up with some pretty broad numbers and I was wanting to nail something down.

my 2500 gallon number is considerably oversized, but that is for a couple reasons. part of the space has to be taken up by the termocline layer, so not the entire volume of the storage is 'usable'. also, I figured bigger is better, as tanks really aren't THAT expensive in this size range (I was looking at splitting the storage among say 3 separate tanks plumbed in series). My actual 'conservative calc' was based on how much it would take to store 24 hours of the 2 ton chiller's capacity. As such, that's:

24,000 BTU/hr * 24 hr * 1 lb/BTU°F ÷ 8.34 lb/gal ÷ 30°F = 2302 gallons

Previously, I had determined how much it would take to provide absolute worst case cooling on my home for the entire peak power period, which is about 3.5 tons for 8 hours. As such:

42,000 BTU/hr * 8 hr * 1 lb/BTU°F ÷ 8.34 lb/gal ÷ 30°F = 1342 gallons

so if all you are looking to do is shift load from the peak power period (for Time-of-use metering), it doesn't take THAT much of a storage system. It's also something that can easily be expanded upon. Starting with just 500 gallons will minimize the cycling, but adding tanks can seriously start to shift load.

[xarralu]

Great, thanks for the info.

[xarralu]

I know prices can't be posted in the open forum, but I was wondering if anyone has any idea of the cost of the 10 ton multiaqua chiller is? I talked to multiaqua a couple of weeks ago just for them to tell me that Trane is the distributor for their equipment in the Dallas/Fort Worth area. I have called and e-mailed every contact in the D/FW Trane office and still have not heard anything. Good 'ol Trane. Their reputation will never change!!!!