Heating, ventilation, and air conditioning (HVAC) systems are essential for maintaining indoor comfort and air quality in various buildings and industrial processes. However, they also consume a large amount of energy and contribute to greenhouse gas emissions. According to the International Energy Agency (IEA), HVAC systems account for about 40% of global electricity consumption and 15% of global CO2 emissions.
To address this challenge, HVAC manufacturers and engineers are constantly looking for ways to improve the energy efficiency and environmental performance of their systems. One of the key factors that affect these aspects is the choice of refrigerant, which is the fluid that circulates in the system and transfers heat between different components.
Traditionally, most HVAC systems have used hydrofluorocarbons (HFCs) as refrigerants, such as R-404A, R-410A, and R-134a. These refrigerants have high cooling capacity and low toxicity, but they also have high global warming potential (GWP), which measures how much a substance can trap heat in the atmosphere. For example, the GWP of R-404A is 3,922, which means that it is 3,922 times more potent than carbon dioxide over a 100-year period.
To reduce the environmental impact of HVAC systems, many countries have agreed to phase down the use of high-GWP HFCs under the Kigali Amendment to the Montreal Protocol, which is an international treaty that aims to protect the ozone layer and the climate. The amendment, which entered into force in 2019, requires the parties to gradually reduce their consumption and production of HFCs by 80-85% by 2047.
As a result, HVAC manufacturers and engineers are seeking alternative refrigerants that have lower GWP and comparable or better performance than HFCs. One of the promising candidates is R-1234ze, which is a hydrofluoroolefin (HFO) refrigerant that has a GWP of only 7, making it nearly 560 times less harmful than R-404A. Moreover, R-1234ze is non-flammable and has similar thermophysical properties and efficiency to R-134a, which is widely used in chillers and heat pumps.
However, R-1234ze also has some drawbacks, such as lower cooling capacity and higher discharge temperature than R-134a, which may limit its application in some HVAC systems. Therefore, HVAC manufacturers and engineers need to optimize the design and operation of their systems to take full advantage of R-1234ze’s benefits and overcome its challenges.
One of the innovative solutions that has been developed is the YORK YVWH Water-to-Water Dual Variable Speed Screw Heat Pump, which is the first screw heat pump in North America to use R-1234ze as the refrigerant. This product was launched by Johnson Controls, a global leader in HVAC solutions, in 2024.
A screw heat pump is a type of rotary compressor that uses two interlocking screws to compress and expand the refrigerant inside a chamber. The screws are designed to mesh together perfectly, forming a seal that prevents any leaks. Compared to other types of compressors, such as reciprocating, scroll, or centrifugal, screw compressors have higher efficiency, reliability, and durability, as well as lower noise and vibration.
The YORK YVWH is a water-to-water heat pump, which means that it uses water as the heat source and the heat sink, instead of air. This allows the heat pump to operate in various climates and seasons, as well as to provide simultaneous heating and cooling functions for different applications. For example, the heat pump can extract heat from a river, a lake, or a wastewater treatment plant, and use it to heat a building, a swimming pool, or an industrial process, while also producing chilled water for cooling or dehumidification purposes.
The YORK YVWH has several features that make it stand out from other heat pumps in the market. First, it uses R-1234ze as the refrigerant, which enables it to go considerably beyond the refrigerant regulations that come into effect starting January 1, 2025, as currently proposed by the U.S. Environmental Protection Agency. By replacing a conventional heat pump with the YORK YVWH, commercial and industrial facilities can significantly reduce their energy use, water consumption, and carbon emissions, while keeping occupants comfortable and processes running effectively.
Second, it has a dual variable speed drive, which means that both the screw compressor and the water pump can adjust their speed according to the load and the ambient conditions. This allows the heat pump to operate at the optimal point of efficiency and performance, as well as to have excellent turndown that enables it to run with as low as 25% of the design-heating load. The dual variable speed drive also reduces the start-up current and the peak power demand, which can lower the electricity bills and the stress on the grid.
Third, it has a high-temperature capability, which means that it can provide water temperatures up to 176°F (80°C), which is the highest among screw heat pumps. This is especially advantageous for high-temperature hot water heating applications, such as district heating, sanitary hot water, or industrial processes. At that temperature, the YORK YVWH can provide 4,050 MBH of heating while simultaneously providing 200 tons of chilled water cooling at 41°F (5°C).
The YORK YVWH is a scalable and flexible solution that can meet the needs of various applications and capacities. Multiple units can be combined or work in parallel with other YORK water-to-water heat pumps, such as the CYK, to increase the system performance and reliability. Each unit is factory-tested to ensure quality and is easy to install and maintain.
The table below summarizes the main features and benefits of the YORK YVWH compared to a conventional heat pump using R-404A as the refrigerant.
| Feature | YORK YVWH | Conventional Heat Pump |
|---|---|---|
| Refrigerant | R-1234ze (GWP = 7) | R-404A (GWP = 3,922) |
| Compressor | Screw | Scroll |
| Drive | Dual variable speed | Fixed speed |
| Water temperature | Up to 176°F (80°C) | Up to 140°F (60°C) |
| Heating capacity | 4,050 MBH | 3,000 MBH |
| Cooling capacity | 200 tons | 150 tons |
| Energy efficiency | High | Low |
| Water consumption | Low | High |
| Carbon emissions | Low | High |
| Noise and vibration | Low | High |
| Reliability and durability | High | Low |
| Scalability and flexibility | High | Low |
The YORK YVWH is a groundbreaking product that demonstrates how a screw heat pump with ultra-low GWP refrigerant can revolutionize the HVAC industry. By using R-1234ze, the YORK YVWH not only complies with the current and future refrigerant regulations, but also delivers superior energy efficiency, environmental performance, and operational flexibility. The YORK YVWH is a sustainable and cost-effective solution that can provide heating, cooling, and hot water for various buildings and industrial processes, while also contributing to the global effort to reduce greenhouse gas emissions.
