Re: Σχετ: Σχετ: [EnergyPlus_Support] Validation -> Zone Mean Air Temperature

Chrisula: In my opinion, temperature difference up to 2.5 C between 2 timesteps (1 min) could not be due to air losses, especially when the openings are closed. However, i don't use infiltration rates but the airflownetwork model (infiltration rates are calculated) using pressure coefficients come from an external cfd analysis.

Simos: The fraction radiant is equal to 0.8. According to your suggestion, I will try to set the second equipment's availability schedule to "off ".

Best Regards,

Giorgos

2012/2/21 Chrisula Vaitsi <solarmech@xxxxxxxxx>

Hi

Temperature differences between measured and simulated data also occur due different infiltration rates of the building and its theoretical model. Have you measured the air losses in the building? Try changing the infiltration rates in the model.

Just a suggestion.

Regards
; )

From: Simeon Oxizidis <simeonagas@xxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Monday, February 20, 2012 9:41 PM

Subject: Ó÷åô: Ó÷åô: [EnergyPlus_Support] Validation -> Zone Mean Air Temperature

Which fraction radiant do you use for the baseboard heater? And from your results which system operates most of the time (and delivers most of the thermal energy)?

Simos

Áðï: Georgios Giannakis <giannakis.georgios@xxxxxxxxx>
Ðñïò: EnergyPlus_Support@xxxxxxxxxxxxxxx
ÓôÜëèçêå: 6:35 ì.ì. ÄåõôÝñá, 20 Öåâñïõáñßïõ 2012
Èåìá: Re: Ó÷åô: [EnergyPlus_Support] Validation -> Zone Mean Air Temperature

Simos,

First of all, thank you for the quick response. The truth is that each office equipment list consists of 2 elements with the following sequence
ZoneHVAC:Baseboard:RadiantConvective:Water

ZoneHVAC:PackagedTerminalHeatPump

Hence, the storage effect should be observed since the major system is a radiation system. Am I right? Maybe I should have a more detailed analysis on how the fractions of radiant energy goes to each surface are calculated.

Best Regards,
Giorgos

2012/2/20 Simeon Oxizidis <simeonagas@xxxxxxxx>

Hi George,

what type of heating system do you have?

If you have an air system obviously it cannot charge the thermal mass of the building since as soon as the room air temperature reaches the setpoint the system turns off (there is not time to add heat by convection to the buildings elements).

The storage effect can be experienced with a radiation system since in that case first the building elements are being charged (by radiation) and then by convection the room air warms up (which triggers the thermostat operation).

I hope that helps.

Simos

Áðï: Georgios Giannakis <giannakis.georgios@xxxxxxxxx>
Ðñïò: EnergyPlus_Support@xxxxxxxxxxxxxxx
ÓôÜëèçêå: 4:35 ì.ì. ÄåõôÝñá, 20 Öåâñïõáñßïõ 2012
Èåìá: [EnergyPlus_Support] Validation -> Zone Mean Air Temperature

Dear forum

In the framework of a fp7 project, we have to validate the simulation model of a building located at Greece-Chania, to check whether the model leads to the same results as specified in terms of provided measurement data. What seems absurd is that once the heating system turns off a sharp 2 C zone air temperature decrease is occured, which in my opinion means that building does not store heat energy, although the inner layer of the buildings envelop consists of materials with high density. We tried to define an extraterrestrial furniture thermal mass (~35 m^2 - it is not exist in the real building) for each office room and it seems that the simulated temperature curve converges to the measured temperature curve. Any answer would really help.

Thanks in advance,
Giannakis G.