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2018-04-30 12:27:52 -0500 commented answer Sequantial load scheme isn't working

@TiejunWu, Hi, thanks for your answer. In reality, the ch-1 starts to work until it meets its 100%PLR, and then the ch-2

2018-04-30 12:27:26 -0500 commented answer Sequantial load scheme isn't working

@TiejunWu, Hi, thanks for your answer. In reality, the ch-1 starts to work until it meets its 100%PLR, and then the ch-2

2018-04-30 11:04:53 -0500 edited question Sequantial load scheme isn't working

SequantialLoad didn't compatible with chiller outlet node temp setpoint Hi, I'm using the E+ 8.7 and I have a trouble of

2018-04-30 11:04:48 -0500 edited question Sequantial load scheme isn't working

SequantialLoad didn't compatible with chiller outlet node temp setpoint Hi, I'm using the E+ 8.7 and I have a trouble of

2018-04-30 10:51:40 -0500 asked a question Sequantial load scheme isn't working

SequantialLoad didn't compatible with chiller outlet node temp setpoint Hi, I'm using the E+ 8.7 and I have a trouble of

2018-01-29 14:56:44 -0500 commented answer How to model a Unitary System with one coil

@Anna Osborne Brannon This is very useful! Thank you!

2018-01-29 14:56:17 -0500 marked best answer How to model a Unitary System with one coil

Hello, I want to model a water-cooled self-contained unit by E+ and each unit includes a supply fan, a DX coil and a condenser. And there is a cooling tower to supply the condensing water to the unit.

Since I'm considering to model each component separately, I'm going to use a Coil:Cooling:WaterToAirHeatPump:EquationFit to model the DX coil. But it needs to be wrapped into a separate AirLoopHVAC:Unitary System based on the existing answers to the questions here here and here.

Anyone know if we still do that? If so, how to set up the coil and the unitary system? Could anyone provide me an example?

Thanks!

2018-01-22 16:47:06 -0500 commented question How to model a Unitary System with one coil

@Avi Thanks for the reminder ! I just reviewed that file and got some knowledge there. But it is not exactly what I need

2018-01-18 15:32:07 -0500 asked a question How to model a Unitary System with one coil

How to model a Unitary System with one coil Hello, I want to model a water-cooled self-contained unit by E+ and each uni

2017-05-25 18:09:36 -0500 asked a question OpenStudio 2.1 Shows Error after Clicking "Thermal Zones" Icon

OpenStudio 2.1 Shows Error after Clicking "Thermal Zones" Icon I want to assign the ideal load to all of my zones. But A

2017-04-21 10:39:27 -0500 received badge  Teacher (source)
2017-04-21 10:20:37 -0500 answered a question Chillers' Weird Operating in Summer Months

Already solved! Just made the condensing water pumps "Continuous" instead of "Intermittent".@rraustad

2017-04-19 16:05:03 -0500 commented question Chillers' Weird Operating in Summer Months

@rraustad The chilled flow mode is always "Constant" because the chilled water pumps are all constant speed.

2017-04-19 10:35:51 -0500 edited question Chillers' Weird Operating in Summer Months

Chillers' Weird Operating in Summer Months I used E+ to model an office building with two chillers. After changing the a

2017-04-19 10:35:04 -0500 asked a question Chillers' Weird Operating in Summer Months

Chillers' Weird Operating in Summer Months I used E+ to model an office building with two chillers. After changing the a

2016-12-02 09:43:33 -0500 commented answer How to Model a Two Compressors Chiller

@energy-metrics, Thank you for your idea! It makes sense to me!

2016-11-30 12:39:49 -0500 asked a question How to Model a Two Compressors Chiller

Recently, I'm modeling a two compressors chiller by EnergyPlus. After reading all the relevant documents, I still did't find anything about multiple compressors. Based on my understanding, the capacity will be changed when the number of working compressors changes. But it will be hard to change the capacity curve in this situation. Does anyone know anything about it? Thanks!

2016-11-09 11:22:25 -0500 commented answer Higher COP values then reference COP
2016-11-09 11:21:45 -0500 commented answer Higher COP values then reference COP

Hey @rkbest, Does the values showed above is the annual average number?It's better to check the hourly value for the whole year. Since I only used the Chiller:Electric:EIR as I mentioned, I'm not sure what does the Chiller:ReformulatedEIR works. Probably the 1st step is to check the rule of "The curve should have a value of 1.0 at the reference temperatures and flow rates specified." And then, read the definition of these 3 curves, which may provides the reasonable range. It is also good to double check the design data for the chiller to make sure all the temperature and flow rate is correct.

2016-11-07 16:36:30 -0500 answered a question Higher COP values then reference COP

Actually, I only used Chiller:Electric:EIR to do the modeling before. But I have a similar situation after using the chiller curves calculated by myself. So I double checked the outputs, including (from .rdd file): Output:Variable,,Chiller Capacity Temperature Modifier Multiplier,hourly; !- HVAC Average [] Output:Variable,,Chiller EIR Temperature Modifier Multiplier,hourly; !- HVAC Average [] Output:Variable,*,Chiller EIR Part Load Modifier Multiplier,hourly; !- HVAC Average [] And then, I found some weird curve feature there and figured out the issue, which is the wrong curve I calculated. Try that to see it is helpful to you.

2016-11-07 15:25:52 -0500 commented answer Cooling Tower Heat Transfer Performance Curve Changes

Thank you for your answers! That is super helpful for me!@aaron

2016-10-31 14:29:28 -0500 asked a question Cooling Tower Heat Transfer Performance Curve Changes

Recently, I used EnergyPlus to model a general building with a variable speed cooling tower. And I select CoolingTowerPerformance:CoolTools as the model type in the baseline model. Actually, we would like to replace that cooling tower with a new one which has a better heat transfer performance in reality as an ECM. So I need to model the ECM model by using another performance curve to increase the heat transfer. I read the definition of that curve in the document, which is using several parameters to determine the approach temperature. That means all the coefficient values are related to a lot of variables. So I have no idea what should I do to only increase the heat transfer performance. Does anyone did the similar changes before. That'll be super helpful! Thanks!

2016-09-16 00:32:01 -0500 marked best answer Simulation Failed After Adding Unmet Load Hours Troubleshooting Measure

I made a building energy model by OpenStudio v1.10.0 and would like to use the unmet hours troubleshooting measure to reduce the unmet hours according to the following instruction: https://unmethours.com/question/359/w...

The model can run successfully. However, the running failed after adding that measure. The details is showed as the following screen shot.

Does anyone get this problem before?

image description

2016-08-15 16:48:06 -0500 asked a question Heat Recovery Chiller and Boiler Work Together

I am working on a complicated heating hot water system, which supplies hot water by boiler (Outdoor air temperature is lower than 60F) or by heat recovery chiller (Outdoor air temperature is higher than 60F). Although there is some suggestions here, but I don't know how to combine it with a boiler. Does anyone has any experience or suggestions can offer? That will be very helpful! Thank you! Some topic about heat recovery chiller: https://unmethours.com/question/1742/

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2016-07-11 16:31:24 -0500 commented answer How to Model a Water-cooled Condensing Unit

@Julien Marrec, Thank you! This is very helpful!

2016-07-11 16:31:06 -0500 marked best answer How to Model a Water-cooled Condensing Unit

I would like to use OpenStudio or EnergyPlus to model a water-cooled condensing unit. Based on that, I need to directly connect the cooling coil of air loop to the condensing water loop. However, the only choice for me right now is the water-to-air heat pump. The problem of this method is that I need to size the heating capacity zero. Is there any better way to model the condensing unit? Does EnergyPlus/OpenStudio has the unit called condensing unit? Does anyone has the similar experience in modeling condensing unit?

2016-07-07 16:31:41 -0500 marked best answer Can We Connect One AirLoop with Another AirLoop

I would like to use EnergyPlus or OpenStudio to model a huge AHU system that supply the cooled air to each floor by using super fans. And each floor also has some terminal boxes that can modulate and heat the cooled air before delivering to the zone. So my idea is as following:

1) Create a central air loop for that huge AHU system 2) Create an extra air loop for each floor that contains the zone and terminal box. 3) Connect each floor's air loop to the central air loop to allow the cooled air to each floor.

Does anyone has the similar experience in connecting two air loops together by some methods? If my ideas can't be true, does anyone has a better idea? Thanks!