Choosing a heat pump starts with the climate. First the series is chosen for the winter design temperature of the site; then the capacity is set from the building's heat loss at that temperature, and the operating point is checked against the water temperature the heating system needs. The need for hot water and cooling decides the indoor unit, and the size of the building decides whether to go with a residential unit or with a commercial outdoor unit or central system. Below we walk through that order using AD products.
Climate first: the design outdoor temperature
Catalogue capacities are always measured at a specific outdoor air and water temperature. Because the capacity of an air source unit falls as the outdoor air gets colder, the real question is what the unit will deliver on the coldest days at your site. Engineers call this the design outdoor temperature; it varies from province to province and drops with altitude. AD's four residential series share the same casing family, but each was developed for a different design point:
- Poyraz series, A −7 / W 55: For Marmara and similar transitional climates where winter stays around −7 °C, such as İstanbul, Bursa, Kocaeli and Tekirdağ. At −7 °C outdoors it delivers 12, 14 or 16 kW of heat with 55 °C water. Refrigerant R290; the 12 kW model runs on single-phase power, the 14 and 16 kW models on three-phase.
- Boran series, A −25 / W 65: For Central Anatolia, the inland Black Sea region and the high parts of Eastern Marmara, where the winter design temperature is below −15 °C. With its vapour injection (EVI) compressor it produces 12–16 kW of heat and 65 °C water at −25 °C; refrigerant R290.
- Vaha series, A +2 / W 55: For the Mediterranean and the Aegean coast, with mild winters and long, hot summers. It delivers 12–16 kW of heat at +2 °C; its R32 cycle is tuned for cooling, and up to three indoor units can be connected to one outdoor unit.
- Ayaz hybrid package, A −30 / W 75: For provinces such as Kars, Erzurum and Sivas, where the winter design temperature is below −20 °C, and for high altitude. An R290 circuit and an R134a circuit work in series; at −30 °C it delivers 12–16 kW of heat and 75 °C water, with the buffer tank inside the package.
When comparing catalogues, look at values taken under the same conditions. Poyraz 12 delivers 15 kW at +7 °C outdoors and 12 kW at −7 °C; Boran 12 is rated at 17 kW at +7 °C and 12 kW at −25 °C. The +7 °C figure looks attractive at first glance, but what will heat the building on the coldest January morning is the figure at the design temperature.
Capacity: the heat loss calculation
Capacity is set by the building's heat loss at the design temperature: the sum of the heat escaping through walls, roof and windows and with ventilation. The calculation depends on insulation, window type, the orientation of the façades and how the rooms are used; in Europe it follows the EN 12831 standard. Choosing with a fixed figure per square metre gives a unit that is too large for a well-insulated house and too small for an old building.
If you have no calculation, the actual consumption of the existing boiler is a good starting point. The gas bills of a few winters show how much heat the building uses in a season; send us that data and we will check the capacity against it.
An undersized unit leans on a backup heater on the coldest days; an oversized one cycles on and off on mild days and means unnecessary investment. An inverter compressor widens the workable range but does not make up for the wrong capacity. An example: in a house whose heat loss at the design temperature comes out at 13 kW, you choose Poyraz 14, not Poyraz 12; the 15 kW that Poyraz 12 delivers at +7 °C is not there at −7 °C. The hot water demand is added to this calculation too.
Heating system: underfloor, radiators, fan coils
The third question is what water temperature the heat emitters in the building need. Underfloor heating usually runs on 30–40 °C water and is the most efficient system for a heat pump. Fan coils usually heat with water at 40–50 °C and cool with chilled water in summer. Radiators sized for a boiler, however, were mostly designed for hotter water.
In existing buildings with radiators there are two routes. The first is to produce water at the temperature the radiators need: Boran supplies 65 °C and Ayaz 75 °C, and Ayaz replaces a boiler on a radiator system without any changes. The second is to reassess the radiators: in buildings whose insulation has been upgraded, or whose radiators were generously sized from the start, 55 °C water is often enough, and Poyraz does the job. Every drop in water temperature makes the unit more efficient; we show the effect in figures in our article on heat pump electricity consumption.
Hot water and cooling
AD series cover heating, cooling and domestic hot water from the same unit; the indoor unit decides how. The hot water volume is chosen from the number of people in the household and their habits; tanked indoor units and the external cylinder connection come in 80, 100, 125 and 140 litre options. For large households it is right to start one class up.
There are two routes for cooling: fan coils or underfloor cooling through the water circuit, or, in buildings without fan coil pipework, direct-expansion cooling through air conditioner indoor units. In coastal regions where cooling takes up most of the year, Vaha stands out because it is tuned for cooling efficiency as much as for heating.
Indoor unit: HİD / HİT, HİDRA, HİDREM
The Poyraz, Boran and Vaha outdoor units pair with one of three indoor units; all three are built in 8, 10, 12, 14 and 16 kW classes, and the class is set by the power of the outdoor unit and the building's heat loss.
- HİD / HİT wall-hung: The pump, expansion vessel and heat exchangers come ready in a casing the size of a combi boiler (510 × 1000 × 350 mm for the 8–12 kW models). It has no tank; hot water is made in an external cylinder. Suited to apartments, offices and shops with little plant space.
- HİDRA with tank: Brings heating, cooling and hot water together in a single floor-standing cabinet. The tank holds 80–140 litres and can be configured as a buffer, a storage tank or a hot water cylinder. A solar collector connects through a second pump, and energy use is tracked on an 8-inch touch panel. The tank options are on the HİDRA indoor unit with tank page.
- HİDREM with direct-expansion cooling: The HİDRA cabinet with a refrigerant cooling circuit added. It heats through the water circuit in winter, supplies wall-mounted air conditioner indoor units in summer, and uses the heat removed by cooling to warm the water in the tank with no extra energy. For buildings without fan coils, the HİDREM indoor unit is the right choice.
Refrigerant: R290, R32 and R410A
The refrigerant determines both efficiency and environmental impact. The R290 (propane) we use in Poyraz and Boran and in the first stage of Ayaz is a natural refrigerant: it has no effect on the ozone layer, its global warming potential is very low, and it is well suited to reaching high water temperatures. The R32 in Vaha keeps its cooling efficiency even when it is very hot outside, which suits cooling-dominated coastal climates. The commercial V and W series outdoor units use R410A. For projects that treat the refrigerant as a specification item, we assess the series together on that basis.
Larger buildings: V, W and Mega
When the heat demand exceeds the 16 kW of the residential series, the choice moves to commercial outdoor units. The V series comes in 20 and 24 kW; it is meant for large and semi-detached villas, small hotels, restaurants and shops. It keeps its rated capacity down to −15 °C, operates down to −32 °C and supplies 55 °C water. The W series outdoor unit is built in six capacities from 28 to 56 kW; several units run together to increase capacity, and some drop out when the load falls. Hotels, dormitories, schools and office towers are the territory of this series.
For demands of hundreds of kilowatts, in greenhouses, housing estates and complexes with a central plant, the Mega central system comes in: 200–1,200 kW capacity, stepless inverter control between 10% and 100%, and heating and cooling from the same unit. Mega is sized separately for each project; the heat loss and heat gain of the spaces, and in greenhouses the target indoor temperature and ventilation needs, go into the calculation.
What information does a quote need?
For us to propose the right series and capacity at the first meeting, the following is enough:
- Province, district and approximate altitude
- A heat loss calculation, or the consumption of the existing boiler over recent winters
- Heating system type: underfloor, radiators, fan coils or a mix of these
- Hot water demand (number of people in the household) and whether cooling is wanted
- Power supply: single-phase or three-phase
- The space available for the indoor unit and the area where the outdoor unit will stand
Send this information through our quote request form, and we will choose the series, capacity and indoor unit together and prepare the quote.
