Publications

Showing 104 results for Author: Zhiming Gao

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  • Sep, 2026

    Conference Paper

    Case Study of Integrating High-Temperature Heat Pump with LiBr-H2O Absorption Chiller for Data Center Liquid Cooling

    Data centers (DCs) are physical infrastructures that support artificial intelligence workloads. The rapid growth of artificial intelligence is putting substantial pressure on the US power grid. Most of electricity consumed by IT equipment, accounting for 50%-60% of total DC power, ultimately becomes waste heat. This heat is dissipated by DC’s cooling facilities, accounting…

  • Aug, 2026

    Journal

    Novel thermal energy storage component: Development, performance, and phase transition diagnosis

    Thermal energy storage (TES) using phase change materials (PCMs) is a promising technology for capturing and storing excess thermal energy for later use. However, challenges such as poor heat transfer efficiency and a lack of modular, scalable designs have limited widespread adoption of TES in real-world applications. This study developed and evaluated modular brick-type a…

  • Jul, 2026

    Journal

    Advanced blade-shaped thermal energy storage device: Development and application

    Thermal energy storage (TES) using phase change materials (PCMs) is a promising approach for capturing and reusing excess thermal energy, yet widespread adoption is limited by low thermal conductivity, bulky configurations, and inadequate scalability. This study presents a modular, blade-shaped TES prototype designed to address these challenges. The device integrates a lig…

  • May, 2026

    Conference Paper

    Advanced Frost Sensor for HVAC Applications

    Frost is a common problem in heating, ventilation, and air conditioning (HVAC) systems that can degrade their efficiencies, leading to excessive electricity consumption. Appropriate defrosting is therefore essential for heat pumps and refrigeration systems. However, these systems typically run the defrost cycle based on a predetermined time interval, a method that does not…

  • Apr, 2026

    Conference Paper

    Zero-CO Residential Natural Gas Furnace

    Residential natural gas furnaces are widely used in the US homes. Manufacturers dedicate significant design and testing resources to meet requirements of design standards. One area of these standards is controlling flue gas carbon monoxide (CO) emissions. To more effectively reduce CO emissions at the flue, we developed a novel catalyst-assisted approach that integrated a…

  • Apr, 2026

    Conference Paper

    Advanced Micro Combined Heat and Power Device

    U.S. buildings account for approximately 40% of total U.S. energy consumption and 75% of electricity use, emphasizing the need for efficient, resilient, and secure energy solutions. Micro-combined heat and power (micro-CHP) systems provide an effective approach by simultaneously generating electricity and recovering waste heat for thermal use. However, current commercial m…

  • Apr, 2026

    Conference Paper

    Performance Evaluation of Low-Cost Condensers Immersed in the Water Tank of a Heat Pump Water Heater

    This paper reports the effect of low-cost immersed condensers on the performance of a heat pump water heater (HPWH) that does not require a water-circulating pump. The proposed design is based on the immersion of an L-style condenser coil through an opening in the top of the water tank. The novel design aims to eliminate the need for the water-circulating pumps, thereby su…

  • Mar, 2026

    Conference Paper

    PINCH POINT ANALYSIS OF GAS COOLERS IN TRANSCRITICAL R1336mzz(Z) HIGH-TEMPERATURE HEAT PUMPS

    The majority of high-temperature heat pumps (HTHPs) operate subcritical vapor compression cycles, where the maximum sink temperature is limited by the critical temperature of refrigerants. In HTHPs with a sink temperature of ≥ 150°C, transcritical cycles overcome this limitation by rejecting heat in the supercritical regions of refrigerant. Supercritical refrigerants in ga…

  • Mar, 2026

    Conference Paper

    Technology Feasibility of High-Temperature Heat Pumps for Industrial Drying Process in the US

    High-temperature heat pumps are a prospective technology for electrifying and decarbonizing industrial drying processes. This study investigates the technological potential of HTHPs in replacing fossil-fuel burners or steam boilers in industrial spray dryers. The performance of HTHPs with three configurations was investigated, including high high-temperature heat pump boos…

  • Mar, 2026

    Conference Paper

    High Temperature Heat Pumps and Their Roles in the Decarbonization of Building and Industry

    Heat pumps have been sought as a promising technology for air and water heating processes in buildings. Several OEMs have been commercializing heat pumps with varying capacities; However, the application has been limited to lower temperatures (less than 70℃). With the recently growing interest in replacing gas-fired equipment for buildings and industrial processes, a new c…

  • Mar, 2026

    Conference Paper

    RENEWABLE MARINE-SOURCE INTEGRATED HEAT PUMP FOR SPACE CONDITIONING, WATER HEATING, AND FRESH WATER HARVESTING IN REMOTE COASTAL AND ISLAND COMMUNITIES

    US coastal and island communities have vulnerable energy infrastructure and high energy costs, which are exacerbated by climate change. A unique opportunity exists to use thermal energy from year-round mild temperature variations to satisfy the broad energy needs of these communities. The US Department of Energy’s Oak Ridge National Laboratory designed a small-scale marine…

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