RE: [EnergyPlus_Support] Time heating setpoint not met

I do not know what you are expecting to see for your zone mean air temperature.

I have already shown you how the daily zone MAT would change for HW tank temperature at 30, 40, 50, 60, 70°C using a HW schedule for different daytypes in five DesignDay objects in the same simulation. You can combine the set point to form a daily schedule for night, morning, mid day, afternoon, etc. That is the best you can do without linking the HW supply temperature to the measured zone temperature. You do not want to do that, because this is not your original system.

I saw the result in your .csv changes from 18 to 32°C. I do not know what you are trying to do by insisting that the simulation must be model your way, with flowrate control, nor HW temperature control.. I told you that I had a care taker for such a system like your in 1954 to adjust the temperature when needed, by controlling the coal fire chimney damper at the furnace. The working temperature was around 40°C for Winter in London, UK.

Most of the time, as the paragraph in your latest e-mails, you are repeating what you want without really think of a system modelling or design requirements.

I did not ask you to use EMS. EMS is not what you said how it is used in the e-mail. The numbers you are quoting below are nearer to a system with zone thermostat control.

By the way, your building description does not match the photo of the bulding for windows and balconeies. So, you will never get the correct simulation result, if you continue in this way.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Sat, 3 Mar 2012 19:43:58 +0000
Subject: Re: [EnergyPlus_Support] Time heating setpoint not met

in my design i dont use EMS , because i think ems is after deisgn , ems related to simulation , i set heating setpoint in my plant :HW outler temperature : 78 C , and i set zone heating setpoint : 30 C , and also in sizing plant : design loop exit temperature : 78 ( for hot water plant ) , but in my result i see the zone air temprature for winter design day is nearly 25-24

From: YuanLu Li <yli006@xxxxxxxxxxx>
To: EnergyPlus_Support <energyplus_support@xxxxxxxxxxxxxxx>
Sent: Saturday, March 3, 2012 10:47 PM
Subject: RE: [EnergyPlus_Support] Time heating setpoint not met

Toorn's question was:

"if i set heating setpoint =30C then i see in the winter design day the zone mean air temperaure is nearly 24-25C ."
could you help me and describe it why this happens?

The above is for Linda, because the color background in the mail was not visible.

I think her heating setpoint is the HW outlet temperature, or the temperature where the HW pump is stopped using EMS

The zone temperature should be below the HW temperature at the inlet of the radiator, when the outdoor environment is at -10°C.

For Tooran:

I have mentioned many times. If your radiator flow rate is fixed, and the boiler temperature is fixed, there is no way that the zone mean air temperature should meet the set point value, at any other conditions, other than the sizing condition.

i set radiator flow rate autosize , to determine in which flow rate of radiator , zone mean air temperature in winter design day is nearly my setpoitn temperature.

With your present settings, the range of temperature is from 18°C to 32°C depending on the outdoor condition and the internal loading, for the three month period. You did not plot the outdoor temperature, so you do not know when the limiting condition occured.

You have removed most of the Output variable display I set in the IDF that I returned to you.

You have already got all the data required by your professor, i.e., the total building heating load requirement, (from the IdealLoadsAirSystem simulation) the zone temperatire variation with boiler temperature (using HW setpoint schedule), and the gas fire capacity (Burner PLR).

If he wanted to control the building temperature by using a fixed boiler temperature and on/off control on the HW pump based on the boiler temperature, you hae done that as well.

i never want do it , i never want to control building temperature

However, you still do not understand the reason for simulation and how to debug the building surface warnings and to select the relevant variables for viewing.

You still do not know the deadband, the setback, and the operating range of a thermostat in EPlus. The zone thermostat is a setpoint register and can be scheduled, and it is not a thermometer measuring the zone temperature.

If you wanted each zone to reach the set zone thermostat value, you must have individual zone control elements, i.e., a valve at each zone radiator activated by the zone thermostat.

ok you r right Dr.Li i dont know all of this .

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: t.t111ir@xxxxxxxxx
Date: Sat, 3 Mar 2012 12:00:38 +0000
Subject: Re: [EnergyPlus_Support] Time heating setpoint not met

i wrote wrong in the yellow highlighted line , the red line in correct

From: Tooran <t.t111ir@xxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Saturday, March 3, 2012 3:26 PM
Subject: [EnergyPlus_Support] Time heating setpoint not met

dear members ,

i want to design the hot water plant loop and i wnat to know what size pump and boiler must have to that their capacity is engough for keeping the zone mean air temperature = 25 C ( i set heating setpoint =25C) for winter design day , but when i run it i see in the winter design day i have time heating setpoint not met and the zone mean air temperature is nearly 20-21-19 C.
if i set heating setpoint =25C then i see in the winter design day the zone mean air temperaure is nearly 24-25C .
if i set heating setpoint =30C then i see in the winter design day the zone mean air temperaure is nearly 24-25C .
could you help me and describe it why this happens?
thanks

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