Residential Package unit and Chiller speculation

[CraziFuzzy]

http://www.aquaproducts.us/home/reve...e-chiller.html

I think, in my case, I'd rather run a water-to-water chiller with an outdoor fan coil for excess heat rejection, than a reversing heat pump type setup. With a water to water, you could run the chiller as necessary to cool the chilled loop and reject to the hot loop, and if the hot loop is over a set temp, run it through the outside coil. This would maximize the ability to recover waste heat from the chiller (and use it for domestic hot water). If hot loop temp is low, it would be supplemented with a high efficiency gas water heater.

With this type of setup, it would be possible to build a 'central plant in a box' type setup, that contained the controls, cold water supply and return, hot water supply and return, and a outdoor (or ground loop) coil supply and return. If gas is an option, it can be installed on the hot loop. In residential uses, I see no reason why you can't use the same loop for heating and domestic, as long as all components are domestic water rated. This type of box can include the pumps, chiller, etc. Accessories such as storage/buffer tanks, etc can be added, as can other items such as solar heat.

There's also no refrigerant work with a box like this. It's a self contained appliance, just like a refrigerator.

[jtrammel]

I think they are stretching with the claim taht it will be more efficient that natural gas heating. How much better COP does the water cooled evap give you? Can you even get 120F water when it's 10F outside?

I thought the advantage of air cooled chillers was having a single central plant along with the dehumidification and building control benefits of chilled water... which is improtant when you are drawing in a lot of outdoor air for ventilation. Not as much the direct energy savings.


The nerd is me really would love to put on of these in when I replace my downstairs system in the next year or two, still install a furnace, but with a hydronic coil and use it as a dual fuel system and use an outdoor reset to adjust the hot water temeprature setpoint for capacity control and maybe even modulate chilled water temperature for humidity control.

I bet I don't even want ot see the prices. I'm guessing a carrier Greenspeed hybrid is looking competitive with it.

I haven't checked it at low temps, it was in ac season when we installed all of the equipment and someone at the church changes filters and cleans coils etc. we havnt been back and it was installed 6 years ago. No complaints of it not meeting the heat/cool demand with no backup heat. It's a 5 ton model that serves 6 small fan coils the rest of church is dx York predators

[jtrammel]

Pricing isn't that bad it's just a heat pump with a pump, tank, and coax hx. It is a small operation right up the road from me in South Carolina

[beenthere]

Made this its own thread in Tech to Tech, since it has little to do with the thread it was in.

[Elfshadow]

I think, in my case, I'd rather run a water-to-water chiller with an outdoor fan coil for excess heat rejection, than a reversing heat pump type setup. With a water to water, you could run the chiller as necessary to cool the chilled loop and reject to the hot loop, and if the hot loop is over a set temp, run it through the outside coil. This would maximize the ability to recover waste heat from the chiller (and use it for domestic hot water). If hot loop temp is low, it would be supplemented with a high efficiency gas water heater.

With this type of setup, it would be possible to build a 'central plant in a box' type setup, that contained the controls, cold water supply and return, hot water supply and return, and a outdoor (or ground loop) coil supply and return. If gas is an option, it can be installed on the hot loop. In residential uses, I see no reason why you can't use the same loop for heating and domestic, as long as all components are domestic water rated. This type of box can include the pumps, chiller, etc. Accessories such as storage/buffer tanks, etc can be added, as can other items such as solar heat.

There's also no refrigerant work with a box like this. It's a self contained appliance, just like a refrigerator.

I know these are commercial but they would be close to what your talking about. They don't have any water tanks though. They actually are pretty small boxes at the lower size, 28x28x19, like I said there are only controls for the refrigerant cycle. These are 410a based off of copeland scrolls. They can be configured for heating, cooling or reversible.

http://www.daikinmcquay.com/mcquaybi...s/Cat_1107.pdf

[CraziFuzzy]

Waterfurnace also makes some nice water-to-water units, down to I think 1.5 ton, and I think they DO have water temp based controls.

[Dallas Duster]

I wonder if any of the major mfg's would ever consider modifiying their split systems to be packaged units with split condensers coils only, so you could reheat the air and even do as Ultra-Aire does and use a heat exchanger to increase moisture removal. THen it's jsut a matter of modulating the amount of vapor going ot reheat vs. the condenser coil.... which of course would require EXV's.

Then again, by the time you've done all that, you might as well just buy a chiller, keep your coil 45F and make hot water for reheat. A chiller eliminates the need for a dedicated dehmidifier, since airflow can be independant of system capacity. I know Crazi is on board with chillers for residential use. Though a WHD is still going ot be a little more economical in a small and medium sized home.

Have you thought about the maintenance on the water treatment ? I have also thought about this idea and to me this seems to be my gray area as for long term system performance.

[Freightshaker]

It would take less innovation than you might think. All it takes to turn a conventional outdoor compressor/condenser unit into a chiller is to connect it to a TXV and heat exchanger (either shell and tube, or brazed plate). The chilled water system itself is also not anything new, as cheap fancoils are already made and readily available in sizes small enough match residential uses, including nice small ceiling mount concealed units, that just need power, t-stat, chilled/hot water, and a condensate drain. Circ pumps, expansion tanks, control valves, are already used in hydronic heating systems. Even conventional hot water tanks makes a very good chilled water buffer tank to avoid excessive chiller cycling. Not the easiest retrofit to an existing home, and some of the savings aren't there, but in a new construction, I don't think I would ever have a home built with conventional ducting at this point.

We had a little old lady that had a chiller on her house. Her husband that passed away was a retired submariner. When he retired he made their basement into a mock submarine right down to the watertight hatches in all the doorways. For his submarine basement ductwork was not going to fly so he made a chiller. The shell in tube was inside hanging on the wall with a TXV.(it just might have been the smallest chiller barrel I have ever seen) It was hooked to a 5 ton trane outside. She had a boiler for heat of course. This was the sharpest home built systems and worked excellent. When we were done servicing the equipment the fella I was with told her due to the boiler age it might not be a bad idea to have a carbon monoxide detector. She laughed and said, "At my age you look foreword to dying in your sleep. I don't think I will be buying one."

[CraziFuzzy]

Have you thought about the maintenance on the water treatment ? I have also thought about this idea and to me this seems to be my gray area as for long term system performance.

With no leaks, there really is no water treatment costs associated with a chilled water loop. Once chemical is added once, it will stay treated fine for many many years.

[Dallas Duster]

With no leaks, there really is no water treatment costs associated with a chilled water loop. Once chemical is added once, it will stay treated fine for many many years.

Unless there is a small leak somehwere. Hey I like the idea as a whole you could count the bad evap coils on one hand if you did have a leaking coil the water goes down the drain.

[Dallas Duster]

With no leaks, there really is no water treatment costs associated with a chilled water loop. Once chemical is added once, it will stay treated fine for many many years.

Then there is back flow inspection.

[xarralu]

Then there is back flow inspection.

Well, maybe not if you had something like this.
I have also looked into different "stuff" for residential use like Absorption Chillers and water-to-water like CraziFuzzy has mentioned. I would like it not only being for humidity control, but also maintaining a set temperature. DX is always going to be a "see-saw" if you want efficiency with it. I would do the same thing that Crazi said earlier in post #27, but at this point I don't think any major mfg. is real close to having a residential chill water rig. I wish someone did, I would be the first in line!

[Dallas Duster]

Well, maybe not if you had something like this.
I have also looked into different "stuff" for residential use like Absorption Chillers and water-to-water like CraziFuzzy has mentioned. I would like it not only being for humidity control, but also maintaining a set temperature. DX is always going to be a "see-saw" if you want efficiency with it. I would do the same thing that Crazi said earlier in post #27, but at this point I don't think any major mfg. is real close to having a residential chill water rig. I wish someone did, I would be the first in line!

That seems pretty neat wonder if it cost an arm and a leg but I think that someone already makes a residential chiller.