Designing Water Cooled Chiller w/ Heat Recovery

[coolwatercool]

Hi All'

I'm designing a new Hotel Bldg. +- 250 Rooms in a tropical area ( no winter )
It's designed to use Water Cooled Chiller for VAC +- 3x300 TR

I'm about to use the heat from the chillers to heat up the water for daily hotel usage
n due to hotel seasons ( peak & low season hotel occupancy ) i intended to combine it with a water heater ( heat pump )

so i asked u all if my hot water diagram is possible to use, because if i looked in some hotel TOR hot water generation diagram is using multiple hot water tank storage in the system

i'm thinking at generating Hot Water @ 55deg C
so if the water from the chiller doesn't reach up to 55deg ( due to low occupancy rate ) then the heat pump will kick in to increase the water temp.

Many thanks will be appreciated

 

[walz]

i think its very possible...this is a true green approach.

but your question is not very clear. Are you asking weather you should use water tanks or not. or don't know.

its really interesting because i was once going to use the chiller heat to remove moisture from dissicant wheels. But project was postponed by the client.

here the concept is same ... energy conservation.
You can really earn much credits if its a green project. Yes you may need to have heat pump as a backup if chillers alone are not sufficient because of less occupancy/load.

 

[coolwatercool]

from a logical view of the system it is possible
but i don't know is it possible technically

from what i receive from Trane or some hotel operators
they suggest to use more than 1 hot water tank because if i only use 1 hot water tank ( like in my diagram ), we will have problems in the mixing of hot water ( not to mention pressure controlling from chiller to tanks n to heatpumps )

 

[ChrisConley]

The issue is primarily lift, you'll have to get a clear picture from the chiller manufacturer what the possible temperatures are. I'm troubleshooting a design with a heat recovery chiller. The issue is getting the cold side cold enough at the same time as the hot side is getting hot enough under all load conditions. Part load conditions are what are hard to picture in these scenarios.

 

[walkes]

The only thing that might be missing is a means of rejecting heat when your domestic hot water load is low. Is there a cooling tower on this loop somewhere?

 

[coolwatercool]

yes there's Cooling Tower in the chiller loop ( the one attached here is only the hot water generation diagram )

 

[KiwiMace]

Bagus. a couple comments:

The heat pump should control the pump start. You might want to spec lead/lag/staging controllers on these pumps initiated from the HP.

I know heat pump products like the mcquay templifier only manage a partial lift and i've seen them backup an electric heat system. York recently came around to talk about a CYK cascading high lift heat pump. You might be OK with a normal unit given the cold water is a lot warmer in the tropics.

Can you put the heat pump in parallel with the chillers + an motorized valve, and share the pumps?

Can you pressurize with the distribution pumps and keep the plant at a lower head?

Pipe the tank to promote stratification.

 

[lurch17]

I do this all the time in Hawaii by building up a hybrid heat-pump/chiller combination. They work great.
I have not ever found an off-the-shelf York/carrier/trane that does a satisfactory job - the machine must be sized and designed for the chilled/hot water load. If water is cheap use an evap condenser. If expensive, use air cooled.

Here is one of my typical systems attached - 57 ton cooling, 130,000 btuh heating domestic water. Pic taken during construction. See the water-cooled cond's on the left-rear inside the cabinet that serves the heat pump compressor. The other three comp's are served by air-cooled cond's next to the cabinet (out of view.

 

[AbbyNormal]

Must be for a resort in Puerto Rico

The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install