Technical Systems for HVAC

[jdelgado]

Hello,

I have some doubts about the technical systems in WUFI Plus V 2.5.3.0.

So, in WUFI PLUS / HVAC systems, we have the following options for "equipment type" in "General":

Mechanical ventilation
Electric heating/DHW
Boiler
District Heating
Heat pump
Solar collector
Water storage
User defined

a) What is this “user defined”? Where do I define it?

b) What distinguish all these equipment’s types, besides the function associated?

c) Which are the efficiencies considered for each equipment type? I haven't found this information anywhere and its crucial to calculate the energy consumptions and to differentiate the performance between different equipment’s;

d) The only system to provide cooling is Heat Pump. What about the typical “splits” and “multiplits”, are considered the same?

e) Solar collector only matches the DHW function. This system always need a support system when there’s no sun radiation enough. What is the support system considered? Eletrical? Gas? Is this important for the calculation?

f) We have "devices" within "systems” And we assign “systems” to the different “share zones” in the model (rooms). How should we fill this frame? For example a heat pump that supplies 3 rooms we should fill with 0.33/0.33/0.33 so the sum is 1? And if the heat pump supplies heat and cool needs, how should we fill the frame? Can you give me an example? Actually, for the same room, I entered 2 systems, one for heating, and one for cooling, each with “1” in the room, respectively. And one system/function/room. Is this ok?

The most important doubt is the efficiencies question.

Thank you very much in advance for any clarification in this matter.

Sílvia Magalhães from FEUP, Oporto

[mpazold]

Hello Sílvia Magalhães,

basically you have to distiguish between the different WUFI Plus versions and scopes.

In WUFI Plus 2.5.3.0 only ideal heating systems are implemented. So the definition of the named eqipment type is not necessary and not regarded. But they are dummys for the other versions and scopes. The device allways act as ideal system with the defined space heating/cooling/air humidification/ air dehumidification capacity. The mechanical ventilation is only used for space ventilation capactiy.

In WUFI Therm, or the current version WUFI Plus free 3.0.3, or WUFI Plus 3.0.3 for example you can add three different types of whole heating system configurations consisting of an gas boiler, an solar collector, combined water storage tank and radiators or TABS systems for the heat distribution to the zones. Those systems are simulated dynamic in interaction with the building envelope, the room climate. -> https://wufi.de/literatur/Pazold,%20Ant ... hermal.pdf

In WUFI Passive, respecitvely wihtin the "Passive house verification" scope, the monthly heat balance method calculation regard the differnt devices represented by different parameters for the primary energy demand.

a) because of this, user defined is a good choise in your version.
b) see above
c) no efficiency is represented for the different devices (with that version).
d) the implemention of split and multisplit units is in progress.
e) with that version the solar collector also acts like an ideal system. No sun radiadion or something is calculated! At least no DHW production or demand.
f) for the ideal system the capacity is distributed via the share zone factors to the zones. For example you have 50 kW space heating capacity shared for 2 zones (0.5/0.5) each zone get 25 kW to keep the indoor climate above the min. design temperture.

best regards,
Matthias

[jdelgado]

Dear Matthias

Thank you so much for this answer. Didn'd understand how i haven't seen this earlier. Only by checking the new doubts query ("General Doubts WUFI PLUS" that you kindly also answered) i have seen this answer.

I think i understand all your answers. I will treat the calculated data from energy consumptions outside the program with efficiencies racios, what is also possible. Could you just clarify this answer in particular:

e) with that version the solar collector also acts like an ideal system. No sun radiadion or something is calculated! At least no DHW production or demand.
How does the program this calculation for SCollectors, this way?

Thank you so much once again.

Best regards
Sílvia