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Laboratory assessment of a demand response controller for rooftop units.

Number: pap. 2535

Author(s) : SARHADIAN R., COBURN B. A., MENDOZA A., et al.

Summary

A major factor affecting the electrical power demand requirements of the air conditioners is the ambient dry-bulb temperature (DBT). Past studies show air conditioners need more power and energy when operating during hot weather, and thereby increase power demand during summer peak energy use periods. The integration of renewable energy, from wind and solar technology, with the electric grid is expected to change the way grid works, including a redefinition of “peak periods” from mid-day to late afternoon. To balance demand and capacity for sustaining grid reliability, utilities offer their customers economic incentives to reduced electricity consumption through demand response (DR) programs. Recognizing the importance of power demand reductions, a laboratory research project is initiated to explore the DR potential and human comfort effects of installing a retrofit controller on a 5-ton rooftop unit (RTU). This paper presents the project findings. The evaluated controller was capable of responding to two distinct DR signals: “moderate” and “high.” Based on the signal, the controller limited RTU’s power demand by modulating the frequency or speed of the compressor and indoor fan. Eight tests were conducted, accounting for variations in indoor and outdoor conditions, as well as the DR event notification types. The outdoor conditions represented air conditioners rating point and elevated climatic setting. The indoor conditions characterized a typical temperature setting with moderate humidity level, and a typical air conditioner rating condition with high humidity level. Results verified controller’s consistent response to the activated DR signals. The implemented DR strategies established the demand reduction potential of up to 60% for the RTU. The outcome of demand-limiting strategies, however, was an alarmingly elevated indoor DBT, indicating to move away from traditional mindset of sacrificing human comfort at peak outdoor conditions to reduce grid demand. Future studies should consider evaluating control technologies with different strategies, and under a 24-hour dynamic load profile following upcoming test standards for DR-capable devices. As the industry continues to explore DR solutions that offer potential for reducing power and energy demand for air conditioners, findings from this project will contribute to the body of knowledge and add value to future research by empirically substantiating advantages and drawbacks associated with control strategies.

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Pages: 12

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Details

  • Original title: Laboratory assessment of a demand response controller for rooftop units.
  • Record ID : 30024600
  • Languages: English
  • Source: 2018 Purdue Conferences. 17th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2018/07/09

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