Reconfigure System Architecture for Low GWP Refrigerants

Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
Partner: Emerson Climate Technologies
DOE Total Funding: $500,000
Cost Share: $500,000
Project Term: October 1, 2019 – September 30, 2022
Funding Type: CRADA

Project Objective

Working with Emerson Commercial and Residential Solutions, the project will deliver a four-loop residential, split, integrated heat pump, capable of space cooling and heating, domestic water heating, energy storage, separate sensible and latent cooling, and minimizing fire hazard. The integrated system comprises four fluid loops, all capable of energy storage:

1. A vapor compression loop (VCS) using propane, which can switch between air conditioning (AC) and heat pump (HP) modes, using a brazed plate condenser/evaporator to heat/cool indoor conditioning water in a hydronic loop for space heating/cooling.
2. A hydronic loop with a storage tank. When there is a space conditioning demand, the hydronic loop distributes cooling/heating capacities to multiple zone terminals, e.g. chilled beam, radiator, etc. When there are no indoor demands but requests from the power grid, the conditioned water circulates between the storage tank and the BHP condenser/evaporator, to store thermal energy via varying the water temperature.
3. A hot water loop for domestic hot water use, i.e. shower, kitchen, etc. The hot water loop is necessary during the cooling season. Upon demands, the vapor compression system will switch from the AC mode, which cools the hydronic loop, to the HP mode for water heating. In the heating season, the hot water loop will serve as a thermal storage additional to the hydronic water storage tank. The water and refrigerant loops respond to grid signals via elevating the storage water temperature.
4. A liquid desiccant (LD) loop with thermal storage for SSLC. This can be an add-on option to any vapor compression systems. The heat grade of desuperheater will be elevated by a thermo-electric module, therefore, it is possible to use low-cost liquid desiccants. Majority of the LD system will be outdoor, such as the solution tank.

Project Impact

This project aims to achieve substantial energy savings in both residential and commercial sectors, potentially saving 816 TBtu annually in the residential sector and 670 TBtu in the commercial sector. Additionally, it seeks to promote the widespread adoption of efficient and eco-friendly HVAC and WH systems that use propane (with a low GWP of 3.3), thus supporting sustainability within the industry. The project will involve the development of a versatile hydronic heat pump system for both space heating and water heating, contributing to the EERE/BTO goals by assisting in the target of reducing carbon emissions per square foot in U.S. buildings by 30% by 2030 compared to a 2010 baseline.

Contacts

DOE Technology Manager: Payam Delgoshaei
Lead Performer: Hanlong Wan

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