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Hot water loop load reset

asked 2019-04-02 09:14:37 -0500

kbk78 gravatar image

updated 2019-04-02 17:53:42 -0500

What is the best way to simulate a Loads reset option so as to supply at the lowest temperature that can meet the heating loads. The design drawing call for the following controls

"DEMAND BASED RESET: HEATING WATER TEMPERATURE SHALL BE RESET BASED ON DEMAND. THE DDC SYSTEM SHALL MONITOR THE COMMAND POSITION OF ALL HEATING WATER VALVES. THE DDC SYSTEM SHALL RESET THE HEATING WATER SYSTEM TEMPERATURE SET POINT DOWN AT A RATE OF 2 DEG. F EVERY 10 MINUTES UNTIL THE WORST CASE VALVE IS OPERATING AT 95% OPEN FOR MORE THAN 10 MINUTES. AT THAT TIME THE RESET THE COMMANDED POSITION OF ALL HEATING WATER VALVES SEQUENCE SHALL INCREASE TEMPERATURE UNTIL THE VALVE RETURNS TO A 90% OPEN CONDITION AT WHICH POINT THE RESET SEQUENCE SHALL RESUME."

This is similar to the Load reset option that eQuest offers. In energyplus we do have a warmest controller for the air side, can such control be simulated on the water side? This is especially beneficial condensing boilers to maximize operation in the condensing zone.

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answered 2019-05-15 00:05:04 -0500

You could try "SetpointManager:ReturnTemperature:HotWater. This object tries to achieve a specific return temperature on a plant loop, but given a min and max range. This is essentially a load-based reset because the greater the load the higher the setpoint will be in order for the return water to stay the same temperature. I havn't used this object like this before, but it's worth a try.

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Asked: 2019-04-02 09:14:37 -0500

Seen: 585 times

Last updated: May 15