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[EnergyPlus_Support] Re: Compare Single zone and multiple zones per floor
Dr. Li , Can I have your email? I would like to send some image rather than text file discussion.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> This is why user always said "I have done what you said and do not know why it does not work." For a 3m x 3m x 3m box, the ground floor or the roof is only 1/6 of the total surface of the zone. There is no ground effect and roof effect. Probably, there is no windows. I have stated in my explanation for the two buffer zones that the ground cooling and solar heating will always make the two end zones different from each another. The roof and ground floor cannot be tested without a adjacent zone. When they come out the same, then you can forget the buffer zones. Basement will change the ground effect to the grouond floor. These are all known facts.
> ===================================Your comments on Chicago is also not for general cases. I am in Toronto. Heating is actually less than cooling because the ground effect. The ground temperature cools in Summer and heats in Winter. The buildings here generally has good insulation, but no ventilation, unless the balcony door is open.. You only need to heat a few degree from 15 to 20°C. When the sun is shining, my unit sometime needed cooling in Winter. Probably because there are hot water pipes running up and down the vertical shafts. For a unit facing North, it is cold during the day. There is about $200 per year heating bill difference between the North and South facing units. (about 1000 sq.ft. 12th floor of a 23 floor building) I hardly turn on the unit for cooling. This is why I kept saying the cooling requirement should be minimized by building design and heat source control, such as venting the dryer air and kitching air out of the apartment.=======================================If you combine these two unit on the same floor, the result will be different. This is why I never test a one zone per floor building for comfort design. The 5 zone model is the best. (four directions and a core.) Heat radiation is proportional to the fourth power of the temperature. If the wall surface is hot and the zone is also hot, less heat would be transferred across the wall. Partitioning a floor would therefore made the floor cooler in the other sections. That is why a one room studio must have HVAC. (This is not one room per floor.) A large penhouse does not need HVAC for all the rooms. The boilers, the machine room would also keep it warm. Energy saving cannot be achieved by just following guidelines.
> Dr. Li
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: sanphawat@...
> Date: Tue, 22 Nov 2011 17:28:38 +0000
> Subject: [EnergyPlus_Support] Compare Single zone and multiple zones per floor
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> I was testing follow you and Jason suggestion. I have created a simple box 3m x 3m, one zone per floor for 15 story as base model and to compare with multiplier model at mid zone. The heating and Cooling in both are almost the same.
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> Once I did another model by creating multiple zones per one floor (15 story building) The result came out different way. I am talking about just Cooling and Heating trend.
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> In Chicago , Heating dominant therefor I think trend should be Cooling (MJ/m2) < Heating (MJ/m2) as my testing model (one zone per floor, 3x3m.)But for multiple zones shows Cooling (MJ/m2) > Heating (MJ/m2).
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> Is there any consideration between one zone per floor and multiple zone per floor? Any thought
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