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Boiling hot temperatures in prototype model of small hotel 90.1-2013

asked 2020-07-08 22:48:57 -0500

Optimulate gravatar image

updated 2020-07-09 09:58:34 -0500

Hi all,

I've been working with the 90.1-2013 protoype model of a small hotel, in climate zone ASHRAE 169-2013-5A.

When running a simulation without any further modifications (using an Amsterdam weather file), I'm getting some very questionable results. The elevator core at the ground floor has temperatue variations between 40 and 95 degrees Celcius (105 - 205 Fahrenheit). The neighboring rooms are of course affected. Particularly the laundry room next door, with similar but delayed and slightly attenuated temperatures. I believe such temperatures would be bad for business. Here is a screenshot of all air thermal zone temperatures:

image description

From top to bottom, the lines represent:

  • Green line: ElevatorCoreFlr1
  • Purple line: LaundryRoomFlr1
  • Pinkish line: ElevatorCoreFlr2
  • Blue line: EmployeeLoungeFlr1

Outside temperature is close to freezing.

I'm using the most recent versions of OpenStudio and EnergyPlus.

Clearly something is quite wrong, which surprises me from a protoype model. Any advice on how I can track down and solve the issue? In the meantime, I'll keep investigating and will update if I find anything.

Thanks!

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I have traced the heat source to several electrical and gas plug loads that seem insanely high to me. Notably: a 32kW elevator using almost 70,000 kWh a year. I'm no elevator expert, but isn't that a bit much for a 4 story building? If it isn't, then I think ventilation needs to be modelled better to prevent all the heat build-up.

Same for the laundry room. Turns out the high temperatures there are not just becasue of the neighboring elevator. The laundry room also has its own very high electrical and gas equipment loads, leading to soaring temperatures.

Optimulate gravatar image Optimulate  ( 2020-07-09 00:38:25 -0500 )edit

Next on the list: heavy loads in the front lounge. The effects of this on the room temperature is masked, due to the kicking in of the HVAC. However, running air conditioning in a hotel lobby on a January day in Amsterdam seems far fetched at the least...

I'm no hotel expert, but altogether, I'm getting the feeling that the prototype model isn't particularly representative for the non-guestroom part of the building? Would love to hear some thoughts on this.

Optimulate gravatar image Optimulate  ( 2020-07-09 00:41:08 -0500 )edit

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answered 2020-07-10 20:09:03 -0500

Jian Zhang gravatar image

updated 2020-07-10 20:10:32 -0500

There are a couple of reasons.

  1. ElevatorCoreFlr1 ZN and LaundryRoomFlr1 ZN are not conditioned but they have high internal equipment load. The heat from the internal equipment loads can only escape the zones through conduction through the internal surfaces or the external envelope, which causes the high temperature in themselves and their adjacent zones. The HVAC system in the adjacent zones are not sized to account for the loads from neighbor zones.
  2. The elevator's schedule fractions seem to be too high. I reviewed a couple of elevator energy consumption data sources and it seems the annual elevator consumption in the small hotel is an order of magnitude higher than those data. Table 4.21 in Thornton et al 2010 (https://www.energycodes.gov/sites/def...) documents the calculation about the elevator design power. I believe it is reasonable. So, the hourly schedule fractions should be reduced. Similar issues would be in LaundryRoomFlr1 ZN but the internal equipment load from laundry equipment is much lower. Our team will address these issues in the future release of the Measure. For now, if your interest is not the internal loads, I recommend you to make a temporary fix to change the Fraction Radiant below from 0.5 to 0. That should remove all heat to the space. See the object below.

ElectricEquipment,

Elevator Coreflr1 Elevator Lights/Fans Equipment, !- Name

ElevatorCoreFlr1 ZN, !- Zone or ZoneList Name

HotelSmall ELEV_LIGHT_FAN_SCH_ADD_DF, !- Schedule Name

EquipmentLevel, !- Design Level Calculation Method

125, !- Design Level {W}

, !- Watts per Zone Floor Area {W/m2}

, !- Watts per Person {W/person}

0, !- Fraction Latent

0, !- Fraction Radiant

0, !- Fraction Lost

General; !- End-Use Subcategory

Let me know if you have further questions.

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Thank you very much for your response. My study wasn't focussed on the internal loads, so I had already shut them off, allowing me to complete my analysis without further issues. Great if this will be improved in a new version.

Optimulate gravatar image Optimulate  ( 2020-07-12 22:41:52 -0500 )edit

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Asked: 2020-07-08 22:48:57 -0500

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Last updated: Jul 10 '20