No ApacheHVAC results visible in Vista

[ieser]

Hello

Simple system was modelled in ApacheHVAC but no results are visible neither in Vista nor VistaPro. HVAC system comprises of 1 hot water loop with 2 boilers, gas and biomass sequenced for different load scenario and solar pre-heating.

Multiplex was created with 105 layers and one room assigned to each layer. One type radiator created and assigned for each room with fixed radiator output (no autosizing carried out). Boiler outputs were also manually specified based on selected models and prior loads analysis carried out based on output from apache systems.

I have no results for 'Systems' section in VistaPro (ie Aache Systems Energy etc.) and under Building Loads section I have results for ApHVAC items related to hot water heating and from solar thermal panels (set as pre-heat for hot water loop return). I have no information about heating whatsoever, no space/room conditioning loads present etc. I presume radiators are not properly attached or sized? They are visible in system browser.

Pictures describing set up available here: https://www.flickr.com/x/t/0098009/gp/uslink/1F5jJ0/

Also questions:

Is there a way of modelling buffer vessel for hot water loop ie to reduce boiler load or to avoid boiler idling. Wondering if possible to asses selected/autosized buffer water temperature, flow rates (in and out) etc.?

Is it possible to asses the load of individual boilers connected in the loop? I have one biomass and one gas boiler that I would like to asses loads for and verify if sequencing is working correctly.

Thanks for help.

[farahghanem]

can you show what you have in Vista?

Apache systems would not have any results, because it is not used if you link ApacheHVAC in the simulation.

[ieser]

Results I can see for on picked winter day are as follows: https://www.flickr.com/x/t/0095009/gp/uslink/85Yg9j

Basically as it can be seen all room load lines lying on the x axis at 0.

I can see some load coming from solar collectors (not much as it winter) so this works but I cannot see the actual energy yield.

Can however figure out different boilers loads by selecting type of fuel used ie System biomass energy and System natural gas energy, so this is OK.

There is also picture of defined radiator: https://www.flickr.com/x/t/0094009/gp/uslink/xr5534 Same one attached to each room (layer) in multiplex.

Any ideas?

[farahghanem]

try selecting a room, and then under the "Room" category in vistapro selecting heating plant sensible load. This should give you the heating load for that room.

[ieser]

Hi I have tried that and did not bring any results either.

What else I tried I used prototype system (one with grey frame) from library, in this case used mechanical extract only and set fan's flow rate to 0 to not model any mechanical extract as this is not required / intended. This seems to work, I was now able to do auto sizing and have some figures populated in field (in green colour). I also reduced size of radiator to smaller one and let auto size to choose how many required in each zone.

Although I do get heating load now, the auto sizing feature is confusing me. I have all zones (single apartments represented as one geometry/block) in multiplex and allowed autozising. Each zone I look at (local edit) has same number of small radiators and heat load, I would expect small apartments to have less radiators, larger more. I cannot do tabular edit either in this case as there only one type of radiator in each zone.

By precise set up of controls I have managed to fairly match the load with previous version of model with electric resistive heaters and apache system, hence avoiding overshooting temperature and curves fairly match (checked only one room though). Not sure if autosizing worked well in this case or what is the best approach to assign the load/number of radiators into zones rather than using auto sizing feature. I have over 100 zones and it would be difficult to manually select emitter(s) to each one or to define different emitter type for each one.

I had to create room with air supply and system with extract that is not used to be able to get it working. Is it the only way? What is the best way to deal with radiator only heating system in ApacheHVAC? Wonder what are your experiences in this areas.

[farahghanem]

frankly I haven't had much experience with radiators as I mostly model for cooling dominant climates, so can't really confirm what is the best way to model it, I assumed you know how to do so and just having trouble with VistaPro.

Do you get unmet hours? that way we can determine if the system is working properly first, then look at why we are not seeing the results.

[ieser]

Well..it's the first time I am modelling this for radiator only system without any mechanical ventilation. That's why decided to create simplest form of multiplex and room without air supply in it to which radiator is assigned. Same layers for each zone.

Didn't work so tried with simplest system from library (mechanical extract only) and set the fan flow to 0 to not have any influence on simulation/building energy. This approach seems to work quite well, just wondered if that has to be done this way. Manual does not help much on this, also the concept of room without air supply is quite confusing to me now as cannot see real application of it.

By analysing results seems like system does what supposed to and model working reliably...with extra fan and ductwork that is not doing anything.

[farahghanem]

maybe if you do not have much mechanical systems in the project, using apache systems would be a better option. Why complicate things with ApacheHVAC?

[ieser]

To explore benefits of using different heat sources for heat network. Biomass boiler for base load, gas for Max load and solar preheat. ApacheHVAC is doing decent job in simulating which appliance is working at which time and what contribution is made to overall carbon emissions.

Gas boiler deals with loads below minimum of biomass and those above its Max. Apache systems can't provide this breakdown. Different control strategies are being tested as well.

[farahghanem]

Ah! that makes sense. I guess you can use the simplest prototype system then as that seems to be working for you.

As to why load results are not showing, maybe check with support if it is a bug in your installation