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HOT2000 - Overriding capacity limits for equipment

asked 2019-08-13 08:11:50 -0600

jdubster's avatar

I'm trying to model townhouses in HOT2000. Since I am grouping units I need to increase the sizes of equipment but the upper limits of the equipment like water heaters, tanks, etc. is very low. Is there a way to override these upper limits?

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answered 2019-08-14 09:54:18 -0600

kanders's avatar

Townhouses aren't supposed to be combined in HOT2000, they're supposed to be modelled individually, and so there would be relatively low limits on mechanical sizing. The exception would be if the townhomes are stacked (units separated horizontally), then you could model them as one building, using the MURB feature available in HOT2000v11.5 and higher. That would allow for larger HVAC equipment sizes.

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Thanks for your response. The townhouses are indeed stacked. I downloaded the latest HOT2K version and couldn't find the MURB feature. Do you know how I can access it?

I was using the Ontario MURB version of v.10.51 and could not find any special feature for MURBs in the software. All equipment sizing limits are ridiculously low forcing me to add multiple suites and multiple HVAC systems which has been extremely time-consuming.

jdubster's avatar jdubster  ( 2019-08-15 14:39:29 -0600 )edit

I have the Evaluator software, but the General software, v11.6, should have the MURB feature. You select Multi-Unit Whole Building as the Building Type under Specifications.

NRCan still has the old ON MURB v10.51 software listed, however I think that's obsolete (I don't think it has any integration with 2017 SB-12, perhaps it was configured for the old ERS 80 code). In v10.51, if I recall correctly HVAC systems were to be modeled independently for each MURB unit.

kanders's avatar kanders  ( 2019-08-15 15:15:57 -0600 )edit

Hi. I tried opening HOT2K v11.6, set the building to "Multi-Unit: whole building", and when I tried to set the Heating Output Capacity to anything over 341200 Btu/h it gives me an error. Is there something I'm missing or will it just not work?

That means as each of my suites use a 95 MBH Heating/DHW combo heater I can't have more than 3 suites to an HVAC system at a time...

jdubster's avatar jdubster  ( 2019-08-21 12:36:54 -0600 )edit

My last resort is to make multiple models one for each suite type in a building which is not preferred. It seems like you can only model the combo unit and the split AC units as a central system and not as independent equipment at the space level. And of course the central system doesn't allow for the large combined capacity of all the units.

Any other ideas would be appreciated. I'm forced to use this software to demonstrate compliance to Part 9 for a small MURB, but the software seems to only want to model a small house and nothing more.

jdubster's avatar jdubster  ( 2019-08-21 12:37:02 -0600 )edit

I see now that HOT2000 has capped the heating capacity at 100 kW, not sure why they did that. Have you tried setting the output capacity from 'user specified to 'calculated'? 95 MBH per unit seems really high - even most single-family detached homes don't have heating loads that high. I'm guessing since its a combo that the heater can modulate down to much lower output capacities - product technical data would indicate this.

kanders's avatar kanders  ( 2019-08-21 12:59:34 -0600 )edit

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Asked: 2019-08-13 08:11:50 -0600

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Last updated: Aug 14 '19