# A Review of Worldwide Strategies for Promoting High-Temperature Heat Pumps
## 4 The Promotion of IHPs over the World
### Usa
The DOE's commitment to industrial decarbonization is further evident in programs like the Technologies for Industrial Emissions Reduction Development (TIEReD) program and the Industrial Demonstrations Program. These initiatives aim to invest in transformative technologies and support their demonstration and deployment, driving progress toward a decarbonized industrial sector [118]. The USA is also financing several R&D projects to demonstrate the economic and technical feasibility of HTHPs, as well as to overcome relevant barriers related to technical aspects. Some of the most interesting ones aim to boost cross-sector decarbonization technologies [118]. For instance, Siemens Energy, Inc. will collaborate with Dow Chemical to advance the design of modular HP systems featuring a two-stage hermetic solution for centrifugal compressors. These modular compressors are designed to prevent refrigerant leakage and offer a smaller footprint compared to conventional compressors. By replacing fossil fuel combustion, these HPs can help decarbonize process steam. The final assembly aims for a COP of 2.56 and a design life of 20 years [118; 119]. That Energy LLC and its partners aim to replace gas-fired industrial boilers with a supercritical CO\({}_{2}\)-based HTHP system that integrates into existing manufacturing infrastructure. The project will develop key components, including a high-temperature ionic liquid piston compressor, two energy recovery devices, and a compact heat exchanger for superior performance. This approach overcomes critical technological barriers to high efficiency using supercritical CO\({}_{2}\). The goal is to achieve a 40% reduction in energy intensity using low global warming potential refrigerants [118; 119]. Oak Ridge National Laboratory (ORNL) will lead a team to develop an IHP system capable of achieving 200n \({}^{\circ}\)C sink temperatures. The project addresses system-level design considerations to maintain efficiency while raising sink temperatures, including waste-heat recovery technology. The goal is to enable the electrification of high-heat industrial processes. The team will demonstrate a cascading HP system using low global warming potential (GWP) refrigerants in transcritical cycles, enhanced efficiency via expansion work recovery devices, and advanced artificial intelligence (AI) process control. By the project's end, they will test a 20 kW prototype [118; 119]. Also, many universities are involved in HTHP-related R&D projects. Purdue University will lead a team to enhance IHPs by developing an internally cooled screw compressor capable of providing higher temperature heat. These HPs offer a highly energy-efficient alternative to fossil fuel combustion, delivering zero-carbon heat when powered by clean energy sources. The project involves additive manufacturing of a screw compressor, researching stable refrigerants and lubricants with low GWP, and optimizing the integration of heat exchangers, thermal storage, and HP systems into industrial processes. An interdisciplinary team will address the lubricant, energy storage, and heat exchanger design for the compressor technology [118; 119]. The University of Maryland and its partners will enhance HTHPs to provide continuous, zero-carbon heat for processes exceeding 200 \({}^{\circ}\)C. To improve existing HP technology, the team will implement a novel injection system using isopropanol refrigerant combined with an efficient heat exchanger system. This approach, utilizing a near-saturation cycle process with multi-stage compression, aims to achieve high efficiency at 200 \({}^{\circ}\)C with a T\({}_{\text{lift}}\) of 100 \({}^{\circ}\)C [118; 119]. Some projects specifically target decarbonization in USA sub-sectors, such as the pulp and paper industry and the food and beverage industry.