K18

• Which is the building right size for a typical K18 installation?
  You should consider the actual thermal load and the additional functions instead of the size of the building. For instance, you can always provide DHW while a 120sqm building not well insulated may require the same thermal load of a well-insulated 300sqm one.
• Which kinds of building are suitable for the K18 heat pump?
  Considering the right thermal load, we can consider one and two-family dwellings, even if already built.
• Can the K18 be installed in an existing building with high temperature radiators (70/80°C)?
  Yes. The K18 can deliver hot water up to 65°C, a temperature high enough for heating even during the coldest seasons, in fact:
  1. The radiators’ dimensions are commonly oversized.
  2. The heating power peak is typically calculated on the few coldest hours during night time for only a few days per year and doesn’t consider the thermal inertia of the building itself that can compensate the temporary deficit of power.
  3. Very often old buildings have been improved with thermal insulation actions (e.g. new window frames). With the K18 the old boiler replacement or integration becomes easier and faster.
• Which are the advantages of a K18 in comparison with an Electric Heat Pump?
  Mainly but not only:
  • The K18 electrical power need is really low: less than half a kW against more than 5 kW required by the electric technology.
  • The K18 is able to perform well even when the external air temperature drops a lot; as a consequence of this, there is no need of power integration with an electric resistance. Due to this, extra energy savings are guaranteed also.
  • The K18 technology is not involved in the F-Gas regulation; in fact it uses a natural refrigerant without any restriction or any specific maintenance.
• Is the K18 easy to be managed and installed?
  Yes. It can be considered as easy to be installed as a boiler.
• Does the K18 require the certified design by a qualified engineer?
  Yes. But only if required by local normative,
• Does the K18 produce DHW?
  Yes. With a DHW preparation tank adequately dimensioned.
• Does the K18 need a condensate discharge?
  Yes. As a condensing boiler does. No more.
• May I use an existing ambient thermostat to control the K18?
  Yes. Even if the optional System Controller with its own room unit will help achieving a better efficiency result.
• May the K18 be managed by an already installed BMS?
  Yes. You can turn on the unit with a voltage-free contact or through the MODBUS protocol (normally with a BMS).
• Can you manage the K18 together with an existing boiler?
  Yes, you can manage a third party boiler with the optional System Controller. The boiler will be used only if the K18 power will need to be integrated.
• How will you manage exhaust piping?
  With 40 Pa of residual head, you can easily bring exhaust pipes up to the roof. Depending on the local normative, you can also manage flue gas exhaust on the wall.
• K18 is for outdoor installation. Which is the best positioning strategy for the unit, looking at the relative building?
  In order to avoid the most possible any unnecessary thermal dispersion due to connection pipes, the closer to the building, the better. You must only guarantee enough air circulation for the finned coil and the fan, and avoid any trouble with people or pets. At least 30 cm far from the closest wall.
• Should the existing water pipe system be always cleaned before installing the K18?
  Yes, it should. Dust and residual metal powder may reduce the K18 heat exchanger efficiency. Please, follow the pipe cleaning procedure that you can find in the K18 installation manual.
• Which is the optimal design temperature for an air source heat pump?
  Heat Pumps’ performances are highly influenced by the water delivery temperature. A variable set point that follows the actual external air temperature is recommended (e.g. 55/60°C when the outdoor temperature is around -5°C; 45/55°C when outdoor temperature is above 0°C). The K18 is ready to work with a variable set point without any further component. With this approach you will also slightly improve the seasonal efficiency.
• Is a buffer tank needed for the heating water circuit?
  No. Anyway even a small buffer tank (100 liters) will improve the system seasonal efficiency, especially during part-load operating mode (the most common working condition during the heating season).
• Which kind of plant components are to be provided for space heating? What should be added if DHW production is needed also?
  The K18 for space heating can be easily managed with voltage-free contact (e.g.: a Chrono-Thermostat, even already existing) as if it was a standard boiler.
  An optional System Controller is available for a more accurate management of the secondary circuit pumps and of a mixing valve.
  Specific DHW tanks with increased surface coils together with the three way valve that switches between space heating/DHW are available.
• What is the System Controller? How it works? Can be remotely managed with mobile devices (tablets, smartphones, etc)?
  The optional System Controller for an advanced K18 and plant management is able to:
  • manage the DHW production with the optional DHW tanks and the optional 3-way diverting valve (both available as accessories);
  • manage a third party boiler existing or new) for power integration;
  • manage 2 secondary circuits (2 direct circuits, or 1 direct circuit and 1 with a mixing valve). An expansion board is available as an accessory to manage a third circuit (direct or with a mixing valve);
  • setup the secondary circuits with different setpoint and parameters (e.g. you can set 2 different weather compensation for the 2 secondary circuits);
  • use the Room Unit, supplied as a standard, instead of a simple Chrono-Thermostat.
  You can manage the K18 via remote controllers (like tablets, smartphones, etc...).
• Can the K18 be supplied with its own circulator?
  Yes. The K18 is available both with and without an embedded high efficiency modulating circulator.
• Does the onboard water pump need a secondary pump towards the plant or is it ready to be used alone?
  An additional secondary water pump can be installed, depending on the existing plant features. The K18 water pump has a residual head of 40 kPa @1.500 l/h.
• Can the external circulation pump be directly managed by the K18?
  Yes, and it is the best option. This way the K18 will be able to manage the water pump according to the Heat Pump operating mode. Moreover also the active anti-icing cycle will be managed, i.e. the water pump will be connected to the electronic board of the unit and turned on in case of too-low water temperature.
• How is the DHW production managed with the K18?
  The K18 will work on a serpentine in the DHW production tank. Its volume will depend on the characteristics of the end user needs (number of people, number of bathrooms, et cetera). 200-300 liters are usually enough. The serpentine must have a wide surface, enough for the power exchange that must be guaranteed between the K18 and the DHW in the tank (3-4 sqm for the 200-300 liter tank). The System Controller (optional) will manage the right water delivery temperature and the 3-way valve.
• What about the legionella cycle?
  The GAHP K18 can produce hot water up to 70°C (return temperature up to 60°C). With this temperature range you can possibly manage a thermal legionella cycle. Anyway other options are available, like UV rays, micro-filters and chemical treatments with chlorine dioxide or hydrogen peroxide.

HEATING MODE⁽¹⁾

ErP Energy Class (55°C application): A++
Working point A7/W35⁽²⁾ | G.U.E. gas utilization efficiency⁽³⁾: 169%
Working point A7/W35⁽²⁾ | heating capacity: 18,9 kW
Working point A7/W50⁽⁴⁾ | gas utilization efficiency⁽⁵⁾: 157%
Working point A7/W50⁽⁴⁾ | heating capacity: 17,6 kW
Max outlet water temperature | heating: 65°C
Nominal max electrical power⁽⁶⁾: 355 W
Sound pressure Lp at 5 metres⁽⁷⁾ | free field, direction factor: 2 | max speed fan: 43,0 dB(A)
Sound pressure Lp at 5 metres⁽⁷⁾ | free field, direction factor: 2 | min speed fan: 40,0 dB(A)

(1) As per calculation methods of EN12309.
(2) Outdoor temperature 7 °C, outlet hot water temperature 35 °C.
(3) Equivalent to COP 4.22 on energy conversion factor of 2.5.
(4) Outdoor temperature 7 °C, outlet hot water temperature 50 °C.
(5) Equivalent to COP 3.92 on energy conversion factor of 2.5.
(6) Water pump electrical consumtpion not included.
(7) Lw sound power 65 dB(A) at max speed fan, 62 dB(A) at min speed fan. Sound power values measured according to EN ISO 9614.
 

DESIGN THERMAL OUTPUT- kW