Figure 1: Frost growth process depends on surface morphology.

Figure 1: Frost growth process depends on surface morphology.

Figure 1: Frost growth process depends on surface morphology.

Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
Partners:
-- Johnson Controls Inc. – Milwaukee, WI
-- Hillphoenix – Conyers, GA
-- University of Illinois at Urbana Champaign – Champaign, IL
-- Isotherm Inc. – Arlington, TX
DOE Total Funding: $590,000
Project Term: October 1, 2017 – September 30, 2020
Funding Type: Lab Award

Project Objective

Oak Ridge National Laboratory will develop a novel, cost-effective and energy-efficient approach to enhance the defrost process for cold climate heat pumps and commercial refrigeration systems utilizing radiations.

Frost formation presents a challenge for both the heat pump and the refrigeration industry, in both residential and commercial applications. Frost buildup increases pressure drop (fan power) and decreases heat transfer, due to the reduced air flow area and thermal conductivity when compared to the base heat exchanger material.

The project team will evaluate the potential of radiation-based defrost (microwaves, UV, visible) processes for deployment in cold climate heat pumps and commercial refrigeration. Radiation defrost can provide a novel approach with significantly lower energy requirements, and can be accomplished continuously or intermittently. To evaluate impact, the team will characterize frost growth on various surfaces, as well as analyze various radiation sources for appropriateness for the proposed application.

Project Impact

The efficiency degradation due to frost growth, and the energy required to defrost, can account for 15-25% of the annual electric energy consumption by heat pumps. The development of effective frost mitigation and defrost technology can lead to more than 200TBtu/year of U.S. primary energy savings.

Contacts

DOE Technology Manager: Antonio Bouza
Lead Performer: Kashif Nawaz, Oak Ridge National Laboratory

Related Publications

  1. Radiation Defrost Techniques, Building Technologies Office Review Meeting 2018, Washington DC.
  2. Kashif Nawaz, Anthony Jacobi, Ahmed Elatar, Brian Fricke, Impact of surface treatment on the condensate retention and frost formation on metal foams, 17th International Refrigeration and Air Conditioning Conference at Purdue, July 9-12, 2018.
  3. Kashif Nawaz, Anthony Jacobi, Ahmed Elatar, Brian Fricke, Frost growth process of various surfaces and implications on heat exchanger performance, Applied Energy (in preparation).
  4. Kashif Nawaz, Ahmed Elatar, Brian Fricke, Modeling of frost growth and defrost process for flat plate heat exchangers, Applied Energy (in preparation).
  5.  Kashif Nawaz, Ahmed Elatar, Brian Fricke, Radiation based defrost process for flat plate heat exchangers, Energy (in preparation).