right choice for heat pump and boilers

[paduk]

Hi,
I have designed a plant to provide DHW and heating for a building.
By the calculation I have got that the heating loads (peaks) are gonna be:
300kW for heating purposes
175 kW for hot water.
The system is going to be made of:
1 heat pump using borehole water connected to a ceiling radiant system to heat the rooms;
3 boilers to provide hot water and part of the heating load.
Now the problem is I dont know how to split the heating load (300KW)between the heat pump and the boilers.
I was thinking to make the heat pump doing 80% of the heating load and than 20% to the boilers (which are going to do also the hot water) but is just an idea without any sort of theorical support.
Have you ever come across this?
Any ideas?

 

[GMcD]

Have you done an energy balance on the mechanical plant versus the boreholes/geo-exchange system? Are you proposing to use the water to water heat pump for heating only? What climate zone are you in? Have you done an economic cost comparison of the fuel/energy sources for generating the hot water? Have you done an energy balance and yearly load profile for the building HVAC demand versus the DHW demand for heating and cooling loads from the mech plant?

There is no rule of thumb when it comes to finding a solution here. The basic engineering has to be done first.

 

[willard3]

Have you had samples taken at the borehole? Have you had the water tested?

If not, what makes you think your heating/sizing calculations are correct?

 

[ChrisConley]

For sizing and using ground-water source heat pumps you need a lot more information than peak load. You should have an idea of the monthly/daily loads as well.

I'm am reading your post correctly? Ground-water pumped out, suck the heat out of it and dump it back into the aquifer?

The split will come from economics. You could size the heat pump for 100% of the load, but the well becomes deeper and the heat pump(s) become more expensive.

Typically I 've sized ground-source loops to do 100% of summer cooling and sized the boiler(s) for the difference, but I'm in a heating dominated climate, I've heard of the opposite in cooling domincated climates.

 

[mkhrais]

what is the borehole?

 

[imok2]

The borehole is a hole in the ground; usually a verticle shaft straight down

 

[willard3]

snip
The borehole is a hole in the ground; usually a verticle shaft straight down
snip

Is that the same as a vertical shaft straight down?

 

[imok2]

I believe it is without the snip snip

 

[ChrisConley]

[quote'] and [\quote] are much less... snippy.