For an evaporator to operate efficiently, it must operate with as high percent of liquid-to-vapour ratio as possible. To accomplish this, the Expansion Device must be able to regulate the flow of liquid refrigerant into the Evaporator at the same rate at which it evaporates. As seen in most systems, the overfeeding and underfeeding of the Expansion Device drastically affects the efficiency of the Evaporator. With the LPA system installed and running, the flow rate is consistently higher with a more evenly modulating Expansion Device. The increase in refrigerant flow and improved control of the expansion device provides

better utilization of the evaporator, creating an increase in pressure and a reduction in superheat temperature entering the compressor. Higher pressure vapor entering the compressor is possible with LPA leading to an increase in compressor capacity, thus providing further efficiency gains.  It is thought that the potential reduction of super-heated refrigerant vapor temperatures via LPA reduces the expansion of reciprocating compressor cylinder walls and therefore improves reliability. 

LPA and the expansion devise

The application of Liquid Pressure Amplification (LPA) to a refrigeration or air conditioning system provides the means by which a considerable reduction in Compressor Discharge Pressure can be permitted. Liquid Pressure Amplification (LPA) is achieved by an hermetically sealed, magnetically driven liquid refrigerant pump which is installed in the Liquid Line from the condenser (or Receiver) and thus sits between the Condensing and Evaporative phases. By overcoming the Liquid Line Pressure Drop, Flash Vapour can be completely eliminated. 

LPA Pressure Enthalpy Chart

Moreover, lower Compressor Discharge Pressures can then offset this elevation of the Liquid Line Pressure. Improvements in Refrigeration System Efficiency of up to 50% are achievable according to operating conditions.   Annual improvements of 20%-40% are more normal due to the limits on savings during the warmer months. 

DX free cooling, or economized cooling, is a smart and energy-efficient method that leverages lower outdoor temperatures to minimize the reliance on mechanical refrigeration. By using an LPA pump to circulate the refrigerant when conditions are favorable, the system can effectively transfer heat outside, bypassing the energy-intensive vapor compression cycle.

This process not only saves energy but also extends the life of the compressors by reducing their workload during cooler periods. It’s an example of how innovative engineering solutions can lead to more sustainable and cost-effective operations in HVAC systems.

DX free cooling systems are particularly suitable for applications where heat extraction is critical, such as in data centers, server rooms, remote electrical switch-gear, underground rail systems, subways, or rail networks. They can handle production cooling capacities ranging from 15 to 150 tons per circuit, making them versatile for various industrial and commercial settings.

Upgrading a refrigeration system can be complex and requires a thorough understanding of the system’s design, operation, and the specific technologies involved, such as Liquid Pressure Amplification (LPA). A qualified engineer will have the expertise to ensure that the upgrade is done correctly, safely, and in a way that maximizes the system’s efficiency and performance. It’s always best to rely on professionals when making significant changes to specialized equipment.

The combination of HY-SAVE technologies, including Liquid Pressure Amplification (LPA), and compressor discharge heat reclaim & disposal can lead to significant improvements in refrigeration efficiency, especially in hot climates. These technologies work together to enhance the performance of refrigeration systems by ensuring optimal refrigerant flow and utilizing waste heat effectively.

The compressor discharge heat reclaim upgrade captures waste heat from the compressor discharge which can be a larger proportion of the THR by the condenser improving the system’s efficiency substantially.

In hot geographical locations, where cooling demands are higher, these technologies can help reduce the energy consumption of refrigeration systems, which is a major contributor to overall electricity usage. By improving the efficiency of these systems, supermarkets and other food retailers can significantly lower their operational costs and carbon footprint, contributing to a more sustainable future.

As a result, the system’s refrigeration efficiency can improve by 15 to 25%, which is a substantial increase, particularly in systems that have been operating inefficiently or have limited condensing duty. This upgrade not only reduces energy consumption but also extends the lifespan of the equipment by reducing wear and tear on the compressor and other components.

In summary, the LPA® pump is a valuable addition to refrigeration systems, especially in scenarios where the design has led to inefficiencies that can be rectified by installing a LPA pump. It’s an effective solution for achieving energy efficiency and sustainability in the refrigeration industry.

The LPA liquid refrigerant pump range has a remarkable track record, having been operational in commercial and industrial settings for over 40 years. This longevity is a testament to the durability and reliability of the technology. With a lifetime performance exceeding 25 years, these pumps represent a long-term investment that can deliver consistent efficiency and energy savings over decades.

Making refrigeration systems more efficient is crucial for energy conservation and cost savings, especially in hotter climates where refrigeration systems work harder to maintain cool temperatures. Here are some strategies to enhance the efficiency of refrigeration systems:

1. Regular Maintenance: Keeping refrigeration systems well-maintained, leak free and thorough cleaning of condenser coils improves efficiency.
2. Temperature Management: Monitor the temperature settings to ensure they are at optimal levels for energy efficiency and operating pressures.
3. Compressor Cooling: Cooler compressor suction temperatures improve compression ratio,
4. Liquid Pressure Amplification: Overcomes liquid line pressure drop improves efficiency by delivering 100% liquid refrigerant to the cooling valves regardless of liquid line length or vertical height, which minimizes the load on compressors.
5. Compressor Discharge Heat Reclaim: This technology reclaims heat from the vapor compression super-heated discharge gas temperatures and transfers this energy to outdoors, further improving system efficiency and reducing the load on the cooling system.

By implementing these measures, supermarkets and other businesses can significantly reduce their energy consumption and operational costs. For specific technologies like Liquid Pressure Amplification, compressor discharge heat reclaim consulting with the manufacturer can provide tailored solutions to maximize refrigeration efficiency especially in hotter climates.

hy-save.net/refrigeration-energy-savings

Refrigeration Energy Savings, 10 to 45%

Please note that the Carbon Trust no longer affords to hand out incentives, refrigeration technologies including Liquid Pressure Amplification LPA pumps.

Depending on the size of plant, its operating hours and the cost of electricity, financial savings can be substantial.
Generally, the larger the plant, the better the return on investment. On a 300 kW plant, energy savings of up to 25% have been seen. With electricity at 8p/kWh, that works out at a saving of £30,000 a year. The capital costs would be around £25,000, giving a payback of under a year.

facts about the LPA liquid refrigerant pump

The LPA liquid refrigerant pump is a robust and innovative component designed for refrigeration systems, with several key features that contribute to its efficiency and reliability:

• Semi-Hermetically Sealed: This design ensures that the pump is less susceptible to leaks and contamination, which is crucial for maintaining the purity of the refrigerant and the overall integrity of the refrigeration system.

• Floating Impeller: The impeller is the only moving part and it operates within a revolving magnetic field. This design minimizes wear and tear, leading to a longer mechanical life.

• External Motor with Magnetic Coupling: The motor’s external placement means that any potential burnout will not contaminate the refrigeration system. Additionally, this design prevents additional heat from being introduced into the system, which could otherwise reduce efficiency.

• Ease of Maintenance: In the rare event of motor failure, the motor can be replaced without the need to shut down the entire system or remove the refrigerant, minimizing downtime and maintenance costs.

• Self-Unloading Capability: The pumps are self-unloading, which eliminates the need for inverter speed control. This feature simplifies the system design and reduces the potential points of failure.

• Long Mechanical Life: With a mechanical life that exceeds 35 years, the LPA liquid refrigerant pumps offer stable and reliable operation over an extended period, making them a cost-effective solution for long-term use.

These features make the LPA liquid refrigerant pump an essential component for achieving energy efficiency in refrigeration systems, particularly in applications where reliability and low maintenance are critical.

Link to the LPA model 875-SS-050-STD-EA

what is the purpose of liquid pressure amplification LPA?

Liquid Pressure Amplification (LPA) is a technique used in refrigeration systems to enhance efficiency and performance. The LPA pump, such as the 809-SS-050-STD-B, is installed in the outlet line of the condenser, after the liquid receiver, to provide the stable pressure required by the expansion valve. This allows the condensing pressure to adjust or ‘float’ according to ambient temperatures, which can lead to energy savings and improved system performance.

The main purpose of LPA is to increase the liquid refrigerant pressure while maintaining the liquid temperature, providing a sub-cooled liquid delivery to the system expansion valves. This is particularly beneficial for systems experiencing liquid line pressure drops, as it helps improve the Coefficient of Performance (COP) and achieve corresponding energy savings.

The LPA pump has been a reliable component in the refrigeration industry for over 40 years, offering efficient refrigerant heat transfer, heat exchange, and latent heat of vaporization. It has been instrumental in enhancing refrigeration performance across various applications.

Liquid pressure amplification in refrigeration (LPA) involves installing a pump in the outlet line of the condenser after the liquid receiver. The LPA pump provides the stable pressure needed for the expansion valve and allows the condensing pressure (and hence compressor delivery pressure) to ‘float’ with ambient temperatures.

LPA® is a registered trademark of HY-SAVE, established in 1986, which underscores the company’s long-standing commitment to innovation in the field of refrigeration efficiency. For those interested in implementing LPA technology or learning more about its benefits, it is recommended to contact HY-SAVE directly for detailed information and guidance.

Google trademark search LPA®-1998/hysave

refrigeration energy savings

To achieve maximum refrigeration energy efficiency and ROI, several strategies can be employed:

1. Lowering Compression Ratio: Reducing the overall refrigeration system compression ratio is key. This can be done by maintaining lower condensing pressures and higher suction pressures within the system.
2. Regular Maintenance: Cleaning air filters and coils, ensuring proper refrigerant charge, and regular system checks can prevent efficiency losses.
3. Liquid Pressure Amplification (LPA): Installing LPA liquid refrigerant pumps in the system’s liquid line delivers 100% liquid refrigerant to the expansion valves, eliminating flash gas and enhancing system flow.
4. Floating Head Pressure: Implementing floating head pressure control allows the system to operate at the lowest possible pressure for current ambient conditions, improving efficiency.
5. Flash Gas Suppression: To eliminate liquid line flash gas, an LPA pump can be installed to suppress the flash before it reaches the system expansion valves. Flash gas does not contribute to cooling and thus represents a loss of efficiency.
6. Improved System Design: Designing systems with shorter liquid lines, minimal bends, and proper insulation can prevent flash gas formation or install an LPA pump to overcome liquid line pressure drop.
7. Sub-cooling: Increasing the level of sub-cooling ensures that the refrigerant remains liquid until it reaches the expansion valve, preventing flash gas or install an LPA pump to deliver 100% liquid to the expansion valves regardless of liquid line pressure drop.

By combining these methods, especially the use of HY-SAVE’s LPA technology, significant energy savings can be achieved, leading to a better return on investment. These improvements not only reduce power consumption but also enhance the overall performance of the refrigeration system, providing more cooling with less energy, which is particularly beneficial in the commercial retail industry. For detailed guidance on implementing these strategies, contacting HY-SAVE or a refrigeration efficiency expert is recommended.

What is flash gas?

Flash gas formation in refrigeration systems is a phenomenon where the refrigerant, intended to be in liquid form, partially vaporizes before it reaches the expansion valve. This can occur due to heat absorption or pressure loss in the liquid line. The presence of flash gas is undesirable as it reduces the efficiency of the refrigeration cycle; the refrigerant in gas form does not contribute to cooling but still requires energy to be circulated by the compressors.

Regarding the relationship between flash gas by weight and volume, as system head pressures are reduced, the percentage of flash gas by weight does indeed expand substantially. For example, 1% flash gas by weight at a condensing temperature of 38°C can expand into 20% flash gas by volume when system head pressures are reduced to condense at 15°C. If the flash gas by weight is 3%, then 42% of the liquid line could be filled with gas, leading to inefficiency and increased operational costs.

The LPA (Liquid Pressure Amplification) pump saves energy by increasing the pressure of the liquid refrigerant in the liquid line, which allows for 100% pressure sub-cooled liquid to be delivered to the cooling coils. This process reduces the system head pressure to a minimum, which in turn lowers the compression ratio and the energy required for compression.

The extent of energy savings achieved with an LPA pump depends on the initial inefficiency of the refrigeration system and the performance gains after the LPA pump installation. In a case study from a dairy farm in Northern Ireland, the implementation of Liquid Pressure Amplification technology in refrigeration systems showed potential for reducing energy consumption in retrofit applications. The study demonstrated that the use of LPA, in conjunction with other measures like liquid injection, can lead to significant energy savings and improved system performance.

By maintaining the refrigerant entirely in liquid form up to the expansion valve, the LPA pump prevents the formation of flash gas, thereby enhancing the efficiency of the refrigeration system.

Case Study

School of Engineering and Design, Brunel University, Uxbridge, Middlesex,

Hadawey, S. A. Tassou*, Y. T. Ge

Case study, dairy farm, northern Ireland, Liquid Pressure Amplification in Refrigeration Systems – Potential for Reducing Energy Consumption in Retrofit Applications