Problem with very high zone tamperature

mangshin · Posts: 6

HI:
I'm new for DesignBuilder user in taiwan.I was downed a free trail of Designbuilder software and builded a house model then try to simulate it.

But i got very high tamperture(40-60)and cooinging/heating load in every room in my simulation result.

I wanna to get a result about if the air condition zone , for example:bedroom,living room..etc,combind with buffer room,for example sun-space balcony or not , how to effect the thermal and cooling/heating load.

Can you help me check the model , and give me some suggest let me know how to modify my model?

Thanks a lot
mangshin

AOG · Posts: 79

Welcome to DesignBuilder Mangshin!

It is difficult to know exactly what are you trying to investigate. As a simple exercise, I have changed the following data in your model:

General target illuminance: 150 lux. Your model has assigned 500 lux, which is a very high value for a house.

Lighting template: Fluorescent, compact. Related with target illuminance, it causes a lighting energy of 6.90 W/m2, instead of the 25 W/m2 in your model.

General internal gains due to equipment: 5 W/m2. Your model has assigned 15 W/m2, also a high value for a house.

Ground floors set as adjacent to ground. Your model has been drawn elevated over the ground, so DB considers automatically that ground floors are adjacent to external air. I'm not sure, but consider this as an error, since there is a garage in the first floor.

Ground floor constructions not insulated. It is intended to take advantage of ground thermal mass.

Monthly ground temperature: 27°C. It is a very intuitive value, thinking in summer time, but more accurate than 14°C in your model. I recommend you to use another tool to get more accurate values, e.g. Ground Temperature Calculator (EnergyPlus).

Ventilation set as calculated (model options) and windows opened permanently to ventilation in 40% of it surface. You model has assigned a 3 ach/h scheduled ventilation rate, which could be low.

Sunspaces windows protected permanently with outside blinds, trying to avoid solar gains during summer period.

With these general changes we get the result for summer design week you can see in the graphic below. You can find also the changed model (DB V1.5.058). It is saved without results, so you have to run a simulation. Please don't consider changed data as optimal, since I'm not familiarized with site climate and building standards in your country.

I hope it is helpful.

Arturo

mangshin · Posts: 6

Arturo:
Thanks a lot for your so fast reply and a great suggestion,it's very useful for me to understand about designbuilder settings about thermal , and how to modify my model.

rahmiandarini · Posts: 43

Hi Arturo,

May I ask, why did you put the ground temperature of 27°C? I'm now also have a problem, to define, what is actually Ground Temperature? and how we get the data of these?

Thanks
Rahmi

AOG · Posts: 79

Hi Rahmi,

Ground monthly temperatures (site details) are temperatures in external surfaces of every construction adjacent to ground. Those temperatures could have great influence in thermal performance of the building: if are high the building will have great heat gains, e.g. through ground floor, if are low the building will have great loses.

As I said, 27°C was a very intuitive value. I have post an answer in other topic you have initiated. Please take a look:

http://www.designbuilder.co.uk/component/option,com_forum/Itemid,25/page,viewtopic/t,1162/

Regards,

Arturo

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