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How to put Seasonal efficiency COP (SCOP) or SEER on Chillers in Design Builder?

asked 2023-06-02 13:08:13 -0500

miguelvargues's avatar

When selecting a chiller in Design Builder's detailed hvac, we are give the possibility to input its COP: In the simple hvac we get to put the seasonal cop. How can we input the season cop in the detailed HVAC?

Should we put it on the rated COP field?

What is the evidence for that?

This makes a huge difference when our seasonal cop is 6.0 and cop 3.2, when compared to a 5.5 cop for the baseline chiller according to ASHRAE Standard 90.1 - 2010 Appendix G.

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answered 2023-06-13 03:40:50 -0500

Luís Filipe S.'s avatar


When inputting the data for the Detailed HVAC, it is important to specify the COP (Coefficient of Performance) at the rated conditions, also known as the Reference COP.

The Reference COP is a numeric field that represents the chiller's coefficient of performance. This value is multiplied by the output of the chiller performance curves.

It's worth noting that the Reference COP should only account for the energy consumption of the chiller itself and should not include energy use attributed to pumps, evaporatively cooled or air-cooled condenser fans, or cooling tower fans. These auxiliary components should be considered separately.

When defining the Reference COP, it is crucial to ensure that the temperature and water flow rates align with the reference conditions. By doing so, you will accurately model the equipment's performance throughout the year, taking into account its variations based on different operating conditions.

Furthermore, when comparing the COP of the proposed equipment with the baseline according to the 90.1 App. G Table 6.8.1, it is important to use the same testing procedure. For instance, you cannot directly compare a SEER (Seasonal Energy Efficiency Ratio) value with an EER (Energy Efficiency Ratio) value, as they represent different testing methodologies and conditions.

I hope this explanation clarifies any confusion and assists you in effectively utilizing the Detailed HVAC feature.

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Thank you for your time. I agree that the same testing procedure must be used, but performance varies according to different conditions. So even if both models use COP, there might be a script that can be written or a performance curve that can be used to approximate the performance of the equipment. On the Portugueses certification, seasonal COPs are used. It's hard to explain to a client that a Class A building can have its performance simulated differently in LEED, bringing the project to way different results. Is there a way to simulate this COP/SCOP, capturing what really happens?

miguelvargues's avatar miguelvargues  ( 2023-09-21 08:59:04 -0500 )edit

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Asked: 2023-06-02 13:08:13 -0500

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Last updated: Jun 13 '23