How to Specify DHW Consumption & Profile

[enerGwizz]

I have a continued frustration that I'm hoping somebody can provide some insight to... When specifying the domestic hot water (DHW) load for a space or group of spaces in Apache, your options are:
- Link DHW consumption to the occupancy profile, for which you must specify the load in gal/h/per (in the US anyway).
- Specify an independent DHW profile, for which you must specify the load in gal/h.

The units of the load are fine in the first option because they are per person and can be suited to each thermal template, BUT the fact that DHW use is linked to occupancy is not okay. For a residential project, occupancy remains high throughout the evening because people are home sleeping, but they are definitely not using DHW at the same rate. And, in general, these two profiles are typically different.

For that reason, it makes sense to specify an independent DHW profile. The problem here, however, is that the units (gal/h) are not per person or per area and will end up getting applied to every space in that template. To use this profile, you'd have to figure out the total load you want and then divide it by the number of spaces in each template.

You'd think you would be able to select the units you want to use, like with internal gains, but I don't see that option.

Am I misunderstanding something? Any advice?

Thanks,
Greg

[chaffinch]

Hi Greg, I can see why this isn't ideal.

I haven't tried this but a possible workaround would be to set the gal/h in the template exactly as you need it but to set the "DHW system" to None. Then for one room (perhaps either the k*****n or bathroom would make sense) override the template setting and set the DHW system to the system you are using. Or you could do it the other way round and leave the DHW system in the template but then override it to none in all spaces but one. Either way this should then just apply the gal/h only once.

Hope that makes sense!