Lincoln's profile - activity

thumbs up. thanks

Awesome, thank you for getting this in the latest release. Good timing! I look forward to testing it.

in reality yes. But I need it to work on a chiller which E+ doesn't support. You think something this common would be su

How would it be corrected, can you please ellaborate? It looks like the chiller:electric isn't supported natively in Ope

How would it be corrected, can you please ellaborate? It looks like the chiller:electric isn't supported natively in Ope

@rraustad, no a desuperheater in not quite right for my application. In my application I'm using a chiller (evaporator a

After wrestling with the measure you sent I was able to create almost what I was looking for. Everything looked good exc

yes, and the heat wuld be transferred into a HW plantloop so it can be used for preheat and reheat.

The documentation clearly states: *1.23.6.1.31 Field: Design Heat Recovery Water Flow Rate* Note that heat recovery

The documentation clearly states: *1.23.6.1.31 Field: Design Heat Recovery Water Flow Rate* Note that heat recovery

The documentation clearly states: **1.23.6.1.31 Field: Design Heat Recovery Water Flow Rate** Note that heat recover

Modeling heat recovery chiller with air-cooled condenser What is the guidance for modeling a heat recovery chiller with

might have something to do with my installation. I always have to include my local gem path to openstudio-standards whic

I found the culprit. The measure requires modules from the openstudio-extension-gem. If I instead save those modules loc

I have it returning results for me but the arguments array in particular is empty. Can you confirm that you're getting b

no arguements found when trying to compute arguements though OpenStudio CLI When executing the --compute_arguments optio

no arguements found when trying to compute arguements though OpenStudio CLI When executing the --compute_arguments optio

Sorry, I had it backwards. SetpointManager:Scheduled:DualSetpoint is applicable is for a plant loop that has both heating and cooling equipment on it. The "high" setpoint is a cooling setpoint, and the low setpoint is used as a heating setpoint. So it should work if the Plant Loop Demand Calculation Scheme is set to DualSetpointDeadband. I've corrected my response above

Sorry, I had it backwards. SetpointManager:Scheduled:DualSetpoint is applicable is for a plant loop that has both heating and cooling equipment on it. The "high" setpoint is a cooling setpoint, and the low setpoint is used as a heating setpoint. So it should work if the Plant Loop Demand Calculation Scheme is set to DualSetpointDeadband. I've corrected my response above.

Take a look at this tutorial on how to setup setpoint managers on condenser loops.

Only simple air-cooled DX objects are allowed to be input into theheating source object type field for the Coil:WaterHeating:Desuperheater object in EnergyPlus.

I need to model a water-to-air heat pump with a Desuperheater for DHW heating. Has anyone found a workaround for this in EnergyPlus?

I'm surprised the Coil:WaterHeating:Desuperheater object doesn't support more coil types like the HeatPump:WaterToWater:ParameterEstimation:Cooling or the Coil:Cooling:WaterToAirHeatPump:ParameterEstimation coil types.

If you also think this would be a nice feature, vote here: https://energyplus.uservoice.com/forums/258860-energyplus/suggestions/16019266-add-more-dx-systems-types-to-provide-waste-heat-fo

Using this setup along with some EMS logic to reset the condenser temperature I can get the WSE to be activated whenever ambient wetbulb conditions allow. However, the chiller doesn't always turn off when it should and stays on with a very low PLR at times because the HX is supplying most of the cooling. I believe this is because the operation schemes that OS is defaulting to.

See timeseries below:

Here are the default schemes that OS translates to E+:

PlantEquipmentOperationSchemes,
  Chilled Water Loop Operation Schemes,   !- Name
  PlantEquipmentOperation:CoolingLoad,    !- Control Scheme Object Type 1
  Chilled Water Loop Cooling Operation Scheme, !- Control Scheme Name 1
  Always On Discrete,                     !- Control Scheme Schedule Name 1
  PlantEquipmentOperation:Uncontrolled,   !- Control Scheme Object Type 2
  Chilled Water Loop Uncontrolled Operation Scheme, !- Control Scheme Name 2
  Always On Discrete,                     !- Control Scheme Schedule Name 2
  PlantEquipmentOperation:ComponentSetpoint, !- Control Scheme Object Type 3
  Chilled Water Loop Setpoint Operation Scheme, !- Control Scheme Name 3
  Always On Discrete;                     !- Control Scheme Schedule Name 3

PlantEquipmentOperation:CoolingLoad,
  Chilled Water Loop Cooling Operation Scheme, !- Name
  0,                                      !- Load Range Lower Limit 1 {W}
  1000000000,                             !- Load Range Upper Limit 1 {W}
  Chilled Water Loop Cooling Equipment List; !- Range Equipment List Name 1

PlantEquipmentList,
  Chilled Water Loop Cooling Equipment List, !- Name
  Chiller:Electric:EIR,                   !- Equipment Object Type 1
  Chiller -2;                             !- Equipment Name 1

PlantEquipmentOperation:Uncontrolled,
  Chilled Water Loop Uncontrolled Operation Scheme, !- Name
  Chilled Water Loop Uncontrolled Equipment List; !- Equipment List Name

PlantEquipmentList,
  Chilled Water Loop Uncontrolled Equipment List, !- Name
  HeatExchanger:FluidToFluid,             !- Equipment Object Type 1
  Non-Integrated Waterside Economizer HX; !- Equipment Name 1

PlantEquipmentOperation:ComponentSetpoint,
  Chilled Water Loop Setpoint Operation Scheme, !- Name
  HeatExchanger:FluidToFluid,             !- Equipment Object Type 1
  Non-Integrated Waterside Economizer HX, !- Equipment Name 1
  Node 118,                               !- Demand Calculation Node Name 1
  Node 122,                               !- Setpoint Node Name 1
  Autosize,                               !- Component Flow Rate 1 {m3/s}
  Dual;                                   !- Operation Type 1

Ideally, I would like to use only a 'PlantEquipmentOperation:ComponentSetpoint' scheme and have both pieces of equipment listed in the scheme with the HX having priority. I don't believe this scheme is supported by OS directly. Does anyone have any ideas on how to create this configuration without manipulating the IDF via measure?

Update: I performed a test where the other two operating schemes were disabled and only the 'PlantEquipmentOperation:ComponentSetpoint' scheme was operational. This resulted in no change at all and the WSE and chiller were staged just like before. Given this disregard my previous question. This was surprising for me as I thought the priority of the other operation schemes would impact how equipment was staged.

I thought it maybe had something to do with the min. PLR and min. unloading ratio for the chiller so I ran another test where these were both set to zero instead of 0.1 and 0.2 respectively. To my surprise, this resulted in quite a large penalty as the chiller's baseload increase by over 100 kW. I'm thoroughly confused now...

I believe the system that you're describing is supported by EnergyPlus/OpenStudio. However, there is not an explicit "3-way valve" option in EnergyPlys like there is in eQUEST. Personally, I think this is a good thing because it requires the modeler to think more about how the system is operating.

As a crude first guess you could set the minimum flow rates on the secondary pump and loop to be equivalent to the rated flow rate of the three-way valve(s). If this is an existing building, trend data will be necessary to figure out what that minimum flow setting should really be. In reality it's probably higher than the rated flow rate of the three-way valve(s).

Checkout this post for more information on modeling primary/secondary loops in OpenStudio/EnergyPlus

This ASHRAE Research Project should point you in the right direction.

yes, put a setpoint manager on the outlet node of the direct cooler. The direct evap cooler in E+ has a field to input the Sensor Node Name. I think OpenStudio fills this input in for you but I would double check...

Controlling the direct cooler in different conditions may be difficult so you could also look at using an indirect cooler on the outdoor air inlet stream.

What's the story with placing multiple fans on airloops in OpenStudio/EnergyPlus? It wasn't legal in OpenStudio for a while but now it is.

How does EnergyPlus handle this? For example, if you placed a fan in the typical location and also placed one on the exhaust air outlet node. How would the fan on the exhaust air outlet node behave if the airloop was in warm-up mode with the OA % set to zero?

Also, does the availability manager for the airloops control both fans or just one?

Out of curiosity, what are some of the some of the biggest changes/challenges energy modelers are seeing on projects using the new version of the standard?

Any lessons learned?

After completing an analysis I downloaded the project database in hopes that it would be possible to upload the results at a later time. After rebooting the openstudio server I'm not seeing how to do this.

Is it possible to terminate and EC2 instance and then restart it and upload a project database?

I like having access to the results but I don't want to keep the server running over long periods of time as the costs can add up.

Is there any update on the BEOpt OpenStudio integration? That would be a very useful feature.

Node pressure is irrelevant unless you're incorporating the AirflowNetwork input objects in EnergyPlus. I don't believe these objects are available in OpenStudio yet.

It just comes down to what load the cooling towers are serving and how they're being controlled. If they share the same basin then they will be controlled/staged in concert to maintain the desired condenser leaving temperature setpoint. Sometimes the cooling towers are serving different loads and can't be modeled as sharing the same basin. I just finished a project where the condenser plant had four cooling towers sitting adjacent to each other with two separate basins and therefore two separate condenser loops. Each condenser loop may have different sequences so they shouldn't be combined.

This only applies to variable speed cooling towers sharing the same basin. If the the towers don't share the same basin the towers should be modeled as separate objects:

1. Combining the towers and using 0.1 for the minimum flow rate would be fine.

2. As long as the towers are sharing the same basin and are variable speed I don't imagine there would be any benefit either way. It's probable worth running a test in E+ comparing the two options.

3. Yes, MaximalCel control saves more energy because of the exact reason you mentioned - the power consumption of the fans depends upon the cube (or a little less) of the fan speed. MaximalCel saves energy under almost all operating conditions if a variable speed fan is used. Further energy savings can be found by floating the tower leaving water temperature control to maintain a constant cooling tower approach temperature.

More information will be required to find the root cause. For example, what kind of valves do you have on your chilled water coils. Did you put the VFD on the primary or secondary chilled water pump? The results could potentially be entirely reasonable depending on your inputs and what you're trying to model. As with most energy modeling tasks - the devil is in the details.

Correct, you need to use TSP in E+. ESP is only the static pressure for ducts and fitting. To get TSP you just add filter, coils and other devises. I think 0.5" w.c. is a reasonable early design phase assumption for coils. TABLE 6.5.3.1.1B of 90.1-2010 provides typical pressure drops for other devices.

Depending how far you want to go into it there're two options:

The first option would be to use the EMS feature of EnergyPlus to control the secondary pumps so the secondary loop always has the desired delta-T (30F). Basically, if the delta-T started to fall the pumps would reduce the flow through the loop. This option is highly recommended if modeling condensing boilers

The other option would be to accept the reality of low delta-T at low part load conditions and set the primary pump to constant speed while making sure it's flow rate is sized to be greater than the secondary pump flow rate.

Low delta-T is nearly impossible to avoid without pressure-independent valves. It can definitely lead to increased gas usage and excess pumping energy.

I would take a look at your pumping configuration. Do you have a primary/secondary loop design or primary only? If primary only, do you have a constant speed pump or is it variable speed?

The specified boiler doesn't have any dedicated capacity control so you're relying on your pump(s) to control the boiler plant's effective capacity.

How many chillers do you have? Are the primary pump(s) constant speed or variable speed?