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15 of September '22

Daikin COLD air conditioner as a heat pump.
From the series "Heating, ventilation, air conditioning - trends 2022".

Energy-efficient heating systems are mainly associated with ground-source heat pumps. An air conditioner, on the other hand, for the average investor, is a cooling device. Meanwhile, an air conditioner is nothing more than an air-to-air heat pump that also functions as an energy-efficient heating system.

However, not every air conditioner is suitable for use as a year-round heating system. When choosing a device to perform such functions, special attention should be paid to ensure that the system is dedicated to the so-called cold regions. That is, in short, it was adapted to work at very low temperatures, otherwise it may happen that the device below a temperature of, for example, -15 ° C will automatically turn off. Daikin offers air conditioners, or rather Daikin COLD heat pumps (optimized for heating), dedicated to year-round heating of rooms in cold climates, with guaranteed operation down to -25 degrees outside temperature.

Daikin COLD

Daikin COLD

© Daikin

Choose from a variety of wall-mounted units such as Daikin Stylish, or skirting units such as Daikin Perfera, with a heat plus function to provide pleasant heating by simulating radiant heat, and with the ability to supply air through the top slot as well as the bottom slot, which in heating mode ensures even temperature distribution in the room.

The Daikin Perfera skirting unit also has two other useful heating functions Heat bust, which quickly warms up the house as soon as the air conditioner starts up, and the skirting heating function, which distributes warm air evenly in the skirting area through the bottom air supply.

These units, come in a variety of sizes and are matched both in terms of functionality, installation options and power offered. Nominal heating capacities reach almost 5.5 kW, and maximum capacities exceed 7-8 kW.

Daikin COLD

Daikin COLD

© Daikin

What sets Daikin COLD - (optimized for heating) units apart from the competition? - Technology and details!

The most important thing is the performance achieved. It would seem that every air conditioner cools as well as heats, but only the power achieved at low outdoor temperatures and the cost of acquiring kWh of heat shows the advantage over the competition.

Significantly, Daikin, as one of the few, provides in the energy labels not only the mandatory in the EU operating parameters corresponding to temperate climate conditions (design temperature -10 degrees), but also those corresponding to a cold climate (design temperature -22 degrees), the publication of which is not mandatory.

Daikin COLD

Daikin COLD

© Daikin

When comparing equipment from different companies, analyzing SCOP, energy classes and the data given in the leaflets, it is worth remembering a very important point. SCOP or energy class is not rigidly assigned to an appliance - it only depends on the conditions in which it operates.

SCOP and energy class are affected by:

  • the design temperature - TDesign, so those -10 or -20 degrees resulting from the climate zone
  • heating power demand - PDesign, i.e. how much power we need at the design temperature
  • bivalent temperature - Tbiv - that is, the moment when our device begins to lack power, although it will continue to heat
  • the limiting operating temperature, the so-called TOL- or operation limit - the lower limit of the device's operation declared by the manufacturer.

It then turns out that an appliance in the A+++ class for a temperate climate (the normative obligation to list the energy class for this climate in the EU), may not cope with operation in a cold climate at all, although its energy class is higher than that for an appliance suitable for operation in a cold climate. Therefore, it is worth carefully analyzing all the units available on the market and inquiring exactly what the data given in catalogs mean.

Daikin COLD

Daikin COLD

© Daikin

What is it about Daikin COLD units that makes them achieve such great performance?

The key to success is the optimization of both hardware and software tailored to the low operating temperatures and room comfort achieved. Let's start with the most important component of air source heat pumps - the unit and its defrost operation.

COLD units have a special design in which the heat exchanger is suspended in the air and there is no bottom tray under it. Water flows freely during the defrost cycle, and thus the possibility of ice building up in the lower part of the exchanger is excluded. Following this, the defrost logic has also been changed. The conditions for the start and stop of defrosting (compressor run time) have been changed, and its time has been shortened by increasing the compressor run frequency. The cycle is therefore more intensive and faster.

Daikin COLD

Daikin COLD

© Daikin

The range of heating power modulation has also been greatly expanded. COLD air conditioners have the letters OH for Optimized Heating in their designation, and the power modulation curves have been shifted so that at -15 degrees the unit modulates heating power up to 4.5 kW. This reduced the number of start/stops of the unit, especially during periods of transition or reduction in heat demand (e.g., change of setpoint, night lowering). All this translated favorably into a high integrated COP.

The unit has several more improvements. The side covers have been moved away from the exchanger plane, eliminating the risk, of snow deposition, and the front grille (grill) has been completely changed, making the unit quieter and the specific sound of the inverter buzzing when operating at low temperatures. It is moved forward by several cm. All this information clearly shows how important details are when choosing a unit.

Daikin COLD

Daikin COLD

© Daikin

A number of improvements have also been applied to indoor units. For example, some wall-mounted units are equipped with a dual-zone motion sensor, which allows air to be directed out of the occupied zone and the setting to be changed when people are not in the room. Horizontal and vertical blades allow for 3D supply.

The maximum airflow in heating mode has been increased compared to the traditional unit, and the fan down range has been extended. When the thermostat in heating mode shuts down the unit, the supply unit continues to operate in super low LLL mode to eliminate the start/stop of the fan and to ensure consistent, even airflow and room temperature measurement.

Daikin COLD

Daikin COLD

© Daikin

In silence mode, the volume drops to 19 dBA - the threshold of audibility.

Daikin Cold units, thanks to the Online Controller module, also have remote control from an Android or IOS smartphone. The Daikin Cold unit can start up on its own in a user-specified mode depending on the indoor temperature and on voice command.

Year-round heating of a house/location with an air conditioner raises a number of questions. However, the excellent operating parameters and attractive design of Cold units arouse great interest among individual investors, and consequently many decide to choose such a method of heating, especially in situations where there is no access to gas, and heating with a fuel stove is not the preferred choice.


For more information, visit the company's Daikin Airconditioning Poland Sp. z o.o. page on the PdA portal.

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