Yan's profile - activity

I built several VRF systems with DOAS using OpenStudio 1.7.0. VRF is used to deal with cooling/heating load, and all the fresh air from DOAS system. I tried to setup the "Outdoor Air Flow Rate During Cooling Operation" of vrf air thermail to 0 in OpenStudio, but when I came back, it will be "autosize" again. And simulation results showed that the outdoor air was double actullay, one from vrf and one from DOAS. I had to use text file editor to close the outdoor air of VRF. Is there something wrong? Thanks.

How to report the "System Node Temperature" for a specific node in OS? I am thinking about using AddOutputVariable measure, but it seems I can only input the variable name and get temperature for all nodes.

In EnergyPlus, I input the node name in the "Key Value" item of the "Output:Variable" section. Where could I input the node name in OS? I am using OS1.7.0.

Same problem, have you found the solution?

I am actually looking for the introduction of the curves so was checking the document "DOE22Vol4-Libraries". Was wonderi

eQuest Fan curve options Is there any reference which describes the details of the fan curves in eQuest library? The mec

I would like to build a hot water loop with condensing boiler.

1. Is there any curve available in OpenStudio?

2. How should I change the curve?

3. I also tried to change the loop leave water T, delta T, but simulation results were totally unreasonable which showed no heating after May. Is there anything else I need to set up?

heat recovery chiller in DOE 2.3 Has anybody successfully simulated heat recovery chiller with significant heating savin

I would like to input "Rated Cooling COP" of "AirConditioner:VariableRefrigerantFlow". The engineer provides both EER and IEER for the unit. Which one should I use to calculate COP? As I know, IEER shows the performance of part load. However, the EER of this unit only shows the unit performance when VRF is operating 99%-100% of its full-size. I think most of the time, the unit will operate less than 98% of its full-size. Does it mean that I should use IEER to calculate the COP but not EER? Thanks.

I would like to add a return fan to an AHU but not quite sure where I should put it in. I put an additional fan in the Supply Equipment side of the air loop, just before the AirLoopHVAC:OutdoorAirSystem. But when I check the idf file, the fan is still in the supply branch and in this branch, there are two fans. Is it correct? What about relief fan?

I assigned a typical VAV system with reheat but there are many heating unmet hours in the core area. After I did further check for node temp as well as air cfm and found:

1) the air cfm is almost fixed all the time, like CAV 2) although I set the sizing air inlet/outlet temp for heating coil in reheat is 13C/35C. However, the heating coil can only heat the air to around 18C, even though the heating is not enough at that time. Therefore, it came out the unmet hours.

Anyone had same problem? Don't know what's wrong with the setup.

Here is the link for my sample model, which is a 5-floor small building with typical 5 zone in each floor: link

Hi, all

I would like to size the system design supply airflow rates for my baseline case based on a supply-air-to-room-air difference (ASHRAE90.1 requirement). I think in EnergyPlus, it is realized by choosing "Temperature Difference" in the "Zone Cooling Design Supply Air Temperature Input Method" under "Sizing:Zone" section. Is it corret? If so, is there any similar function in OpenStudio? I didn't find the related function in OpenStudio.

Yan

Dear All,

I am trying to close outdoor air during unoccupied mode by defining availability schedule of Controller:MechanicalVentilation. I can successfully do it in EnergyPlus, but I cannot find the controller:MechanicalVentilation in OpenStudio. Is there anybody know where the controller is located in OpenStudio? (I am using version1.5) . Thanks.

Best wishes,

Yan

I used the measure "Tariff_Selection_Flat" to calculate the cost of purchased chilled water/hot water. In the measure, the unit for district cooling/heating is "dollar/kBtu". However, results show unreasonably low cost in dollar. It seems the unit in the measure should be "$/therm". Is it a bug in the measure?

Dear All,

I have a problem when simulating a very simple building using Sketchup Make and OpenStudio 1.5.0.

I created two OS spaces in Skethup and didn't use "Set Attributes for Selected Spaces" (I plan to complete this part in OS). Then I launged OS, created two thermal zones and assigned the two spaces to thermal zones seperately. After adding thermostat, space type (I used '189.1-2009-Office-Whole Building -Md Office' in library which includes people, load, outdoor air ...), I added the 'Packaged Rooftop VAV with Reheat' system to the model and didn't change any default numbers. Finally, the two thermal zones were connected to the demand side of the air loop.

However, when I clicked the simulation bottom, two errors stopped the simulation:

Object=CONTROLLER:MECHANICALVENTILATION, name=CONTROLLER MECHANICAL VENTILATION 1, Required Field=[Zone 1 Name] was blank. Object=CONTROLLER:MECHANICALVENTILATION, name=CONTROLLER MECHANICAL VENTILATION 2, Required Field=[Zone 1 Name] was blank.>

I exported idf file and used E+ to check it, and it seems in the component 'Controller:MechanicalVentilation', the "Zone 1 Name""Design Specification Outdoor Air Object Name 1""Design Specification Zone Air Distribution Object Name" are missing. No one "DesignSpecification:ZoneAirDistribution" item is created.

Actually I didn't have this problem using previous OS and Sketchup version. Is there anything I miss when creating the model? Anyone has the same problem before? Thanks.

Best wishes,

Yan

I would like to create a dome roof in OpenStudio, just like half of an egg shell ...

It seems that EnergyPlus, OpenStudio cannot accept the curves, and it's necessary to break the dome into many triangles or other plane shapes.

I watched the YouTube video of Creating Complex Geometry for an OpenStudio model and am thinking about creating a dome in Sketchup and then transfer to OpenStudio model. However, I don't understand how to transfer the complex geometry (such as a sphere) into OpenStudio model in the video. I tried to use "Experimental Workflow" - "Merge Sketchup Groups to OSM in background". It works for shapes without curves but doesn't work for cylinder ...

Anyone knows how to transfer complex sketchup groups to OSM? Or any good advice for creating dome roof?

Thank you so much.

Yan

I tried to set up radiant heating and cooling system with regular VAV using OpenStudio 1.7. When I run the simulation, there is an error "Overlapping heating and cooling control temps in radiant system". I adjusted the cooling and heating T of radiant heating/cooling system, but it didn't work. Have you ever experienced this error? Or is there anything else I need to take care of when I build the radiant heating/cooling system with VAV? Thanks.

I have one building with two design options. One applies air source heat pump (simulated as ZoneHVAC:PackagedTerminalHeatPump); the other uses water source heat pump (simulated as ZoneHVAC:WaterToAirHeatPump). Results show WSHP has much more heating than ASHP which seems not reasonable to me. I checked the hourly report and found for ASHP case, heating coil (Coil:Heating:DX:SingleSpeed) did not run at the same time with supplemental electric heating; while in WSHP case, heating coil (Coil:Heating:WaterToAirHeatPump:EquationFit) often run at the same time with supplemental coil. Any control difference between ASHP and WSHP units?

@rraustad, I see, thanks

@rraustad, actually eio file shows the autosized OA are same, but hourly report says hourly OA are different, that makes

@rraustad, there is no DOAS, and I setup outdoor air in "DesignSpecification:OutdoorAir" in both WSHP and ASHP cases. Ho

@rraustad, yeah, I think that's the point, why air flow rates are different when autosize is used.

@rraustat, both cases are autosize, but I checked air flow rate and do find that WSHP has higher air flow rate than ASHP

@rraustat, yes, when I compare the sum of DX heating coil rate + supplemental coil rate, WSHP higher than ASHP, if the l

@rraustat, yes, when I compare the sum of DX heating coil rate + supplemental coil rate, WSHP higher than ASHP

@rraustad, the minimum OAT for compressor is 17.6F, and supplemental electric DX heating coil does not run when the DX h

@rraustad, the minimum OAT for compressor is 17.6F, and supplemental electric DX heating coil does not run when the DX h

@rraustad, thanks for your advice. I checked the control, it does have some influence, but not too much. I use the same