What is a heat pump?
A heat pump is a device that transfers heat against its natural flow, moving it from a cooler area to a warmer one. It can either cool or heat a space according to the need. During the summer, it removes heat from the indoor space at lower temperatures and expels it outdoors at higher temperatures.
Heat Pumps operate based on vapor compression cycle, which can be divided into four steps:
- The compressor compresses the low-pressure refrigerant vapor increasing its pressure and temperature, and then discharges it into the condenser;
- In the condenser, the high-temperature vapor releases heat and condenses back into a high-pressure liquid;
- When it passes through an expansion valve, its pressure and temperature drop significantly;
- In the evaporator, the low-pressure liquid refrigerant absorbs heat, evaporates into a low-pressure vapor, and then enters the compressor to repeat the cycle.
Different types of heat pump
Heat pumps are classified according to the heat source (where the heat is taken from) and the heat vector (where the heat is transferred). We will focus on air-to-water and water-to-water types.
Air-to-water heat pumps
This type of heat pump uses the same components as a chiller but includes a four-way valve that allows the cycle to be reversed. Additionally, the heat exchangers must be reversible so that they can operate as either a condenser or an evaporator, depending on the operating mode.
The heat exchanger on the source side is a tube and fin type, through which air is forced by a fan. On the user side, the heat exchanger can be either a brazed plate or a shell and tube (direct expansion) type. There is a significant difference in volume between the source and user-side heat exchangers, resulting in different refrigerant capacities.
The tube and fin heat exchangers on the source side are larger than the brazed plate or shell and tube heat exchangers on the user side. When the unit operates in cooling mode, the source exchanger acts as the condenser, containing high-pressure vapor and liquid refrigerant, while the user-side exchanger contains low-pressure vapor. In heating mode, the roles reverse: the smaller exchanger contains high-pressure vapor and liquid, while the source (larger) exchanger contains low-pressure vapor. Consequently, the amount of refrigerant required in cooling mode is greater than in heating mode. To compensate for this difference, a liquid receiver on the liquid line is charged during heating operation and discharged in cooling mode.
Another important difference between a heat pump and a chiller is that heat pumps both source and user-side heat exchangers are equipped with proper distribution devices to ensure efficient operation as evaporators. This contrasts with a chiller, where the source side (condenser) does not have a distributor.
The system drives the inversion, and the unit receives a signal to switch operating modes based on the system's requirements.
The source and user-side heat exchangers can be of different types:
- Brazed Plate (BPHE)
- Shell & tube DX (S&T_DX)
- Shell & tube Flooded (S&T_FL)
BPHEs are used in mini, small, and lower-end medium-sized units. For larger capacities, Shell & Tube exchangers are common. Large water-to-water heat pumps typically use flooded-type heat exchangers. This design significantly reduces the approach temperatures, resulting in higher efficiency and an extended operating range compared to units with direct expansion (DX) types.
On the other hand, heat pumps with inversion on the refrigerant side typically have a more limited capacity range compared to the previous type, and the choice of heat exchanger technology is restricted to reversible types. Mini and small sizes use BPHE, while medium sizes use S&T DX.
The refrigerant inversion is achieved with a four-way valve, like air-to-water heat pumps. In this case, the source and user heat exchangers are similar in volume, eliminating the need for a liquid receiver to compensate for differences in refrigerant volume between operating modes.
With inversion on the refrigerant side, the hydraulic system is much simpler.
As mentioned earlier, this type of inversion is more common in mini to medium units, which typically use scroll compressors and brazed plate heat exchangers. Large capacity units, on the other hand, often use flooded heat exchangers, which offer higher efficiency compared to direct expansion types but cannot reverse operation. Therefore, in large-capacity units, the inversion is usually performed on the hydraulic side.
From small to medium air-to-water heat pump plants
The R-32 Small Inverter EWYT-CZ heat pump
Daikin offers a wide range of air-sourced heat pump units, including the Daikin R-32 EWYT-CZ. This air-cooled scroll heat pump is designed for small to medium sized buildings, providing both comfort cooling and process cooling. With a cooling capacity range of 16 to 90 kW and a heating capacity range of 16 to 90 kW, it features full inverter technology and operates efficiently over a wide temperature range, from -20°C to 46°C in cooling mode and from 20°C to 35°C in heating mode.
Learn more here to find out the R-32 EWYT-CZ heat pump as a solution for hotels in Slovenia
Daikin EWYT-CZ heat pump supplied for hotel application
The R-454C high-temperature Small Inverter heat pump EWYE-CZ
Daikin's air-sourced EWYE-CZ high-temperature heat pump features R-454C refrigerant ensuring both efficiency and environmental sustainability. Its operating range allows water to be supplied from 20°C to 70°C, even in extreme conditions such as harsh Nordic winters or summer when domestic hot water is required, making it an excellent choice for decarbonising domestic heating. The range includes eight sizes from 16 kW to 70 kW, all equipped with Daikin Inverter Scroll compressors and operating in ambient temperatures from -25°C to 40°C.
Daikin high temperature EWYE-CZ heat pump
From medium to large air-to-water heat pump plant
The R-32 air-sourced heat pump EWYT-B-
With a capacity range from 74 kW up to 1220 kW, the EWYT-B- heat pump can produce hot water up to 60°C at ambient temperatures up to 35°C. Thanks to its flexible design, it can meet the needs of various applications, including residential buildings, hotels, offices, and hospitals.
Water-to-water heat pumps
This type of heat pump is used when geothermal sources are available or when low-temperature heat is accessible due to a process. It can be utilized for heating-only purposes or seasonal cooling and heating with reversible operation. There are two types of water-to-water heat pumps:
- Reversible on the water side
- Reversible on the refrigerant side
For the first type, the heat pump reversible on the water side is like water-cooled chillers. The key difference lies in the regulation parameter: instead of using the fluid temperature at the evaporator, it uses the temperature at the condenser. These units can be used for heating only or in reversible applications, in which the system must handle the reversibility, while the unit simply changes the set point from the condenser to the evaporator and vice versa.
From small to medium water-to-water heat pump plants
Daikin offers a wide range of water sourced heat pumps that provide high heating and cooling capacities while ensuring thermal comfort. These features make them versatile and suitable for a wide range of applications, like residential applications, office buildings, and hotels.
For these kinds of applications, the modular water-to-water heat pump EWW(H)(L)T-Q offers a plug-and-play solution for easier building management and can produce hot water up to 60°C. This unit features a new modular approach to system design, introducing additional flexibility in configuration. This allows the required capacity to be achieved by combining smaller units piped together and controlled as one. It consists of three base modules with capacities of 100, 125, and 160 kW, featuring Daikin-designed scroll compressors and R-32 refrigerant, which has a low Global Warming Potential (GWP).
When a higher water temperature is required than that typically offered by modular units, the Daikin EWWH-J- range should be considered. The Daikin EWWH-J- screw heat pump is a water-to-water heat pump, reversible on the water side, renowned for its compactness and reliability. This unit is exceptionally efficient thanks to its semi-hermetic, single-screw, infinitely variable compressor, which performs admirably at both full and part load. The heating capacity ranges from 106 to 243 kW and is optimised for use with R-1234ze refrigerant. It can also provide a condensing discharge temperature of up to 75°C for high temperature heating applications. It can also provide chilled water temperatures down to -5°C by adding glycol to the standard unit.
Daikin EWWH-J- series heat pump
From medium to large water-to-water heat pump plant
Large applications require appropriately sized systems, typically served by larger units with inverter screw compressors that can achieve higher capacities. This is the case with the VZ family, which in its version with R-1234ze refrigerant can provide water temperatures up to 75°C. The VZ range is renowned for its high efficiency and low environmental impact. Cooling capacities range from 443 to 1525 kW and heating capacities from 409 to 1924 kW, the heat pump version can produce hot water up to 65°C with water-side reversibility. The Daikin EWWD-VZ screw chiller is a water-cooled inverter screw heat pump solution that guarantees both efficiency and sustainability. It is available in both land and marine versions with a cooling capacity range from 449 to 2100 kW. This unit is equipped with a single screw inverter driven compressor and is available in three efficiency versions. Key features of the VZ range include market-leading efficiency and the ability of the heat pump version to produce hot water up to 75°C with water-side reversibility. These features make it an excellent choice for residential applications, ensuring both high performance and environmental sustainability.
Learn more here to find out Daikin supplied 7 EWWD-VZ heat pumps for a hospital renovation project.
Daikin EWWD-VZ unit provided for hospital renovation project in Estonia
Heat pumps for Residential Application
The EWYE-CZ air-to-water inverter heat pump uses low-gwp refrigerant R-454C, making it an excellent choice for space heating and domestic hot water. It can provide hot water up to 70°C and is ideal for apartment buildings, multi-family homes and detached houses, covering a wide range of applications. It can be combined with different types of terminals, including fan coils, and traditional radiators. Thanks to Daikin's advanced core compressor technology, this heat pump ensures reliable hot water production even in extreme conditions, such as harsh Nordic winters or in summer when domestic hot water is still needed. A low-noise version is also available, making it particularly suitable for noise-sensitive applications.
Heat pumps for Industrial Application
Daikin heat pumps are a highly efficient alternative to traditional gas boilers, offering up to three times greater efficiency. These versatile heat pumps have capacities ranging from 10 to 2400 kW and can produce hot water up to 90°C. Daikin also offers cascade systems that combine air-to-water and water-to-water units for optimum energy efficiency and high-temperature output. In addition, heat recovery solutions allow simultaneous heating and cooling, maximising energy use efficiency. Please find more information in the white paper here below and contact us for further information.
Download the “HVAC system optimization in industrial facilities” Paper
Frequently Asked Questions on Daikin Heat Pumps
Where are Daikin heat pumps manufactured?
Daikin heat pumps are manufactured in Italy, at the headquarters and heart of Daikin Applied Europe, located in Ariccia (Rome). This factory is dedicated to producing high-quality HVAC equipment, including two main types of heat pumps: air-source and water-source.
Cick here to visit Daikin chillers product page.
Click here to visit Daikin heat pumps' product page.
How to purchase a Daikin heat pump?
Click here to send us a contact request and get more support for your needs
How to rent a Daikin’s heat pump?
Get in touch with us for additional support by clicking here.
How to get support for Daikin heat pumps?
Click here to get all the assistance you need.
How to buy spare parts for a Daikin heat pump?
Contact us for more information.