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Active indirect solar hot water collector modeling

asked 2016-07-12 12:41:23 -0500

Alex Vlachokostas gravatar image

updated 2016-07-12 13:47:28 -0500

I am trying to simulate in OpenStudio (OS) a similar version of the SolarCollectorFlatPlateWater.idf, example file in E+, using the available OS components. The idf example file is an active direct system (meaning there is no heat exchanger involved. The water itself picks up thermal energy from the collectors and goes to the storage tank).

In contrast, I want to add a heat exchanger component (i.e., make it an active indirect system). I have identified which components to use as shown at the attached images. More specifically, the following image showsimage 1 the Supply side (which is a solar collector and a pump) and the Demand side (which is a fluid-to-fluid heat exchanger and storage tank -modeled with the WaterHeater:Mixed object-). Then the next image image 2 shows the Supply side (which is a fluid-to-fluid heat exchanger and storage tank) and the Demand side (which is an auxiliary water heater-modeled again with the WaterHeater:Mixed object-).

Am I missing any outstanding OS components in the modeling workflow? Of course, the HVAC system of the building is something different and it is modeled apart. I am still far away from just hitting the 'Run' simulation button and troubleshooting the model so any tips are very welcomed and appreciated.

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answered 2016-07-19 16:14:04 -0500

Alex Vlachokostas gravatar image

updated 2016-07-20 14:23:22 -0500

Although I asked feedback on an active indirect solar hot water loop I came to realize that an active direct solar hot water loop is mostly used in EnergyPlus and DesignBuilder. Following the SolarCollectorFlatPlateWater.idf and DesignBuilder's tutorial for hot water loops with an auxiliary water heater I successfully modeled and ran the OS simulation. For whoever might find it useful I attach screenshots of the loops. The correct setup is as follows: 1) Plant DHW Loop with sub-loops: Plant DHW Loop: Water Heater Side and Plant DHW Loop:Domestic Hot Water Side image description 2) Plant Collector Loop with sub-loops: Plant Collector Loop: Storage Tank Side and Plant Collector Loop: Collector Side image description 3) Addition of WaterUse:Equipement image description

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@Alex Vlachokostas, I understand that you have added a Water Heater and used it as an tank (and also to link the first loop to the second as it has 4 nodes) but I dont get why you added the second water heater, do you also use as a storage tank ? or does it work as regular water heater and consumes fuel? And how do you do to use it as a tank, is just by setting the maximum capacity to 0W or are there other parameters you change ? Thanks :)

Raghda Derbel gravatar image Raghda Derbel  ( 2018-09-20 03:49:35 -0500 )edit

answered 2016-07-12 15:23:24 -0500

Adam Hilton gravatar image

updated 2016-07-12 15:24:03 -0500

You need pipes and setpoint managers. I feel like you probably already know that though.

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OS will add pipes automatically, but definitely need some controls on those loops!

MatthewSteen gravatar image MatthewSteen  ( 2016-07-12 15:35:04 -0500 )edit

Thank you. The pipes are auto-populated in OS. Also, set-points will be set later on -internally at each object. I am just wondering if there is any mistake on the modeling work flow that I followed. Thank you though for your answer.

Alex Vlachokostas gravatar image Alex Vlachokostas  ( 2016-07-12 15:40:15 -0500 )edit

I think there should be hyperlinks on the heat exchanger. Did you ensure that you dragged the correct one in from the 'My Model' tab?

Adam Hilton gravatar image Adam Hilton  ( 2016-07-12 15:47:59 -0500 )edit

I uderstand exctly the connection that you proposed, but I cannot connect WaterHeater:Mixed component with other loops, because of the lack of connectors. Do you have any idea regarding this? How could I connect WaterHeater:Mixed with more than one loops?

isidoros siderakis gravatar image isidoros siderakis  ( 2017-05-09 06:13:40 -0500 )edit

Yes you can, it has four nodes. Just drag it from the 'My Model' tab when you're adding it for the second time, not the 'Library' tab.

Adam Hilton gravatar image Adam Hilton  ( 2017-05-10 07:49:40 -0500 )edit

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Asked: 2016-07-12 12:41:23 -0500

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Last updated: Jul 20 '16