Refrigeration Air Chiller System Evaporating Temperature, Constant or Variable - AirChiller

Hello everyone,

I am currently working on simulating a cold room storage using Refrigeration Equipment, and I am referencing the Refrigerated Warehouse example that utilizes the airchiller object - Fig.1 - (more details).

I have a question regarding the Refrigeration Air Chiller System Evaporating Temperature output variable, defined in the EnergyPlus documentation as the 'saturated evaporating temperature.'

I've plotted it over the simulation time and observed that it remains constant throughout, specifically at -24 °C, as specified in the 'Rated Cooling Source Temperature' within the airchiller object - Fig.2 -.

Can anyone clarify whether this value is expected to be constant during the simulation or if it should vary with time? Your insights would be greatly appreciated.

Thank you!

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Fig.2 image description

902

Zakaria

asked 2024-01-21 08:47:54 -0500

14.1k

Aaron Boranian

updated 2024-01-22 16:24:21 -0500

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I believe the output for the Refrigeration Air Chiller System Evaporating Temperature remains constant, corresponding to the Rated Cooling Source Temperature input for the air chiller. This conclusion is based on a simulation where the air chiller was OFF during the simulation runtime, and the Refrigeration Air Chiller System Evaporating Temperature consistently matched the -24°C which is exactly the Rated Cooling Source Temperature.

In the provided figure, the compressor's electric power and heat transfer rate, plotted on the left, both equil zero since the refrigeration system is turned off. Nevertheless, the evaporating temperature persists at -24°C ( on the right), precisely matching the Air Chiller's Rated Cooling Source Temperature.

Based on these observations, it seems that E+ does not independently calculate the evaporating temperature; rather, it appears to directly pass the Rated Cooling Source Temperature input as an output.

I would appreciate confirmation or additional insights from anyone familiar with this.

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