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1) You want to use the PIU system if you have fan-powered boxes in your VAV system. You need to be able to capture the fan energy used by those boxes, and this is the only system that can capture that fan power. This will not resolve your unmet hours, but this is the correct system for modeling FPBs.

2) A throttling range of 2F is very tight, particularly with a VAV system. You may want to read the help files in eQuest in regards to throttling ranges for VAV boxes - 4F is very acceptable, even 6F would probably pass muster (as indicated by the eQuest help files). All of our eQuest models use a throttling range of 4F.

3) Unconditioned zones next to conditioned ones absolutely can have an impact. If this is what was happening, the zones next to the unconditioned spaces would have the underheated hours - is this the case?

Baseboards should be, in almost all cases, specified as Thermostatic. This means that the baseboard will max out it's capacity before calling for heat from the main system. Presumably, if baseboards are installed, you'd want these to do the majority of the heating in each space.

With that said, it seems counter-intuitive that you would have both heating installed in the VAV boxes, and also have baseboards installed as well.

In general, I'd look at how you've specified your heating & cooling at the system and zone levels. It definitely sounds like a controls issue, if you've got multiple zones simultaneously heating and cooling. It'd be easier to provide more focused answers if you can post a link to your actual model...

1) You want to use the PIU system if you have fan-powered boxes in your VAV system. You need to be able to capture the fan energy used by those boxes, and this is the only system that can capture that fan power. This will not resolve your unmet hours, but this is the correct system for modeling FPBs.

2) A throttling range of 2F is very tight, particularly with a VAV system. You may want to read the help files in eQuest in regards to throttling ranges for VAV boxes - 4F is very acceptable, even 6F would probably pass muster (as indicated by the eQuest help files). All of our eQuest models use a throttling range of 4F.

3) Unconditioned zones next to conditioned ones absolutely can have an impact. If this is what was happening, the zones next to the unconditioned spaces would have the underheated hours - is this the case?

Baseboards should be, in almost all cases, specified as Thermostatic. This means that the baseboard will max out it's capacity before calling for heat from the main system. Presumably, if baseboards are installed, you'd want these to do the majority of the heating in each space.

With that said, it seems counter-intuitive that you would have both heating installed in the VAV boxes, and also have baseboards installed as well.

In general, I'd look at how you've specified your heating & cooling at the system and zone levels. It definitely sounds like a controls issue, if you've got multiple zones simultaneously heating and cooling. It'd be easier to provide more focused answers if you can post a link to your actual model...

1) You want to use the PIU system if you have fan-powered boxes in your VAV system. You need to be able to capture the fan energy used by those boxes, and this is the only system that can capture that fan power. This will not resolve your unmet hours, but this is the correct system for modeling FPBs.

2) A throttling range of 2F is very tight, particularly with a VAV system. You may want to read the help files in eQuest in regards to throttling ranges for VAV boxes - 4F is very acceptable, even 6F would probably pass muster (as indicated by the eQuest help files). All of our eQuest models use a throttling range of 4F.

3) Unconditioned zones next to conditioned ones absolutely can have an impact. If this is what was happening, the zones next to the unconditioned spaces would have the underheated hours - is this the case?

Baseboards should be, in almost all cases, specified as Thermostatic. This means that the baseboard will max out it's capacity before calling for heat from the main system. Presumably, if baseboards are installed, you'd want these to do the majority of the heating in each space. You should also be specifying a capacity (or -1 for no capacity) - if you don't put a value in, the baseboard will autosize and may give you heating where you don't want it. Check your SV-A report to see what baseboards you are getting.

With that said, it seems counter-intuitive that you would have both heating installed in the VAV boxes, and also have baseboards installed as well.

In general, I'd look at how you've specified your heating & cooling at the system and zone levels. It definitely sounds like a controls issue, if you've got multiple zones simultaneously heating and cooling. It'd be easier to provide more focused answers if you can post a link to your actual model...