[Equest-users] Refrigeration version - mechanical subcooler

[Phil Jordan]

I remember this being tricky to add. Check out the “Hierarchy Rules” (step 9) on page 9 of the DOE2 Refrigeration Dictionary:
http://doe2.com/download/doe-22/DOE22Vol2r-DictionaryRefrigeration.pdf
(Looks like the doe2.com site is down so I’ve attached the relevant pages.)

Also attached are my notes on how I had simulated mechanical subcooling in prior models (in an earlier version of eQUEST – v3.61b, I think – but hopefully should still apply to the latest version).

Regards,

Phil Jordan

From: Equest-users <equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>> On Behalf Of Brian Fountain via Equest-users
Sent: Wednesday, March 25, 2020 6:00 PM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Refrigeration version - mechanical subcooler

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I have a model of a refrigerated warehouse in the refrigeration version of eQUEST.  It is running in version 7174 currently.

I am trying to add a mechanical subcooler to the model.  I can add the subcooler keywords, the PS-H for the subcooler is generated but so far despite many control keyword iterations, I am seeing no load on the subcooler and no impact on the refrigeration system with its inclusion in the model.

Currently, my inputs are:


"Subcooler 1" = SUBCOOLER
   TYPE             = MECHANICAL
   ATTACH-TO        = REFG-SYSTEM
   REFG-SYSTEM      = "Refrigeration System"
   CAPACITY         = {#PA("Subcool Cap TR")*3413}
   DESIGN-SUBCOOL-T = 40
   SST-SUBCOOL-TD   = {60}
   SUPERHEAT-DT     = {101-90}
   TEMP-CTRL        = SATURATION-DT
   SATURATION-DT    = 40
   SUCTION-CIRCUIT  = "Low Temp Suction Circuit"
   ..
"Subcool liquid circuit" = REFG-CIRCUIT
   TYPE             = LIQUID
   ATTACH-TO        = SUBCOOLER
   SUBCOOLER        = "Subcooler 1"
   ..

Has anyone successfully added mechanical subcooling to a refrigeration version simulation?

Many thanks,

Brian
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Example 1:
"Suction Group A (LT) is subcooled by Suction Group AS (MT)"
1. Define suction circuit for the subcooler and attach it to the suction group of the system doing the subcooling (MT)

2. Add subcooler to refrigeration system being subcooled (LT)
   a. Attach to REFG-SYSTEM
   b. Enter subcooled T from RS
   c. Temperature Ctrl = THERMOSTAT
   d. Suction Circuit = suction circuit defined above in step 1.
   e. Refrigeration System = system being subcooled (LT)
   f. Trunk Circuit = liquid circuit of system doing the subcooling (MT)

3. Attach liquid circuit of system being subcooled (LT) to subcooler defined in step 2.

4. Input subcooler capacity and subcool/suction TD (aka, approach) from RS.

(5. Liquid circuit of system doing the subcooling (MT) should remain attached to the refrigeration system doing the subcooling (MT) - good to check)

Example 2:
"Suction Group AS (MT) is self-subcooled)"
1. Define suction circuit for the subcooler and attach it to the suction group of the system doing the subcooling (MT)

2. Add subcooler to refrigeration system being subcooled (MT)
   a. Attach to REFG-SYSTEM
   b. Enter subcooled T from RS
   c. Temperature Ctrl = THERMOSTAT
   d. Suction Circuit = suction circuit defined above in step 1.
   e. Refrigeration System = system being subcooled (MT)
   f. Trunk Circuit = liquid circuit of system doing the subcooling (MT)

3. Attach liquid circuit of system being subcooled (MT) to subcooler defined in step 2.

4. Input subcooler capacity and subcool/suction TD (aka, approach) from RS.