ON/OFF control of different modes
For each of the two operation modes, Air-to-Water and Air-to-Air, the thermal ON/OFF variables are different:
1. The leaving water temperature, measured by the plate heat exchanger, is used to control the Air-to-Water space cooling and heating operation.
2. In case of domestic hot water, the thermal ON/OFF factor is the water tank temperature provided by the temperature sensor integrated in the tank. The temperature difference between the target and the thermal ON temperature can be set, which is five degrees Celsius by default.
3. The room temperature, measured by the room thermostat, determines the demand for Air-to-Air space cooling and heating, and can also be used to operate Air-to-Water space heating and cooling. Keep on reading to learn how that works.

The maximum system combination ratio is 200% as simultaneous operation of the modes is not possible. 100% combination ratio applies to the hydro unit and 100% combination applies to Air-to-Air indoor units. For example, a 9 kW outdoor unit can operate with 9 kW Air-to-Air and 9 kW Air-to-Water modes.

Operation during simultaneous Air-to-Water demand
How can hot water for domestic use and Air-to-Water be operated simultaneously when required? To manage this, the operation time setting is necessary for alternating the modes. In the graph below, the upper two horizontal lines represent space heating or cooling and domestic hot water demand, and the lower two horizontal lines represent the operation mode. During time frame 1, a demand for space heating or cooling occurs. The system operates normally to cover that demand. At some point in the day (time frame 2), depending on the user’s demand pattern, the water tank temperature will drop below the thermal ON temperature which generates a request for the domestic hot water operation. When there is simultaneous demand for both modes, domestic hot water is prioritised by default as the usual domestic hot water demand pattern, with peaks in the morning and evening, concentrates the operation request a couple of times a day. The system will cover the demand for domestic hot water during the maximum time set, switching modes back to space heating or cooling if necessary. Space heating or cooling will operate for a minimum time of five minutes by default (setting #3024) to protect the system, and to a maximum time while there is still demand (time frame 3). If the domestic hot water tank temperature is still below the target temperature (time frame 4), a second reheat cycle will start to cater to the demand for domestic hot water.

There is a range of options and default values for the field settings which can be modified according to your project specifications:
• The maximum time for domestic hot water operation (#3025) is 30 minutes by default. That is approximately the duration of every reheat cycle, considering a thermal ON temperature of 40 degrees Celsius and a target temperature of 53 degrees Celsius.
• The time for space heating or cooling operation after domestic hot water (#3026) is, by default, set at three hours. This should give enough time dedicated to space heating or cooling for reaching room temperature without interruption.

Booster heater operation
The booster heater of 3 kW is built inside the ClimateHub water tank. It can be operated to support domestic hot water production, increase efficiency and reduce the operating time compared to the case of not operating the booster heater. The last stage of the domestic hot water operation achieved by water coil is very inefficient and takes a lot of time. As the temperature difference between the water in the tank and the coil is reduced, the heat transfer efficiency is also gradually reduced. As an option, the system can be set to finalise the last stage of domestic hot water operation with support from the booster heater, avoiding a second domestic hot water operation cycle carried out by the heat pump.

The delay time can be defined for the activation of the booster heater after the heat pump starts the operation of domestic hot water (#3032). With the default settings, the last ten minutes of the domestic hot water operation will be supported by the electric booster heater (see the rectangle in the graph below), which will operate until the water tank temperature reaches its set point. By default, the delay time is 20 minutes, but it can be extended to up to 95 minutes, depending on the domestic hot water operation time.

Adding Air-to-Air to the system
How does the system operate when adding the Air-to-Air mode? To explain this, a configuration will be used to meet the demands of domestic hot water, Air-to-Water heating and Air-to-Air cooling. In summer, the system provides Air-to-Air cooling and domestic hot water. Priority setting between Air-to-Air cooling and Air-to-Water modes is necessary to anticipate for simultaneous demand. Additionally, the maximum operation time for the priority mode and the minimum operation time for the non-priority mode have to be set by field option settings.

In winter, thanks to the combination of Air-to-Water and Air-to-Air modes in one system, the house can be quickly heated with the rapid heating function for Air-to-Water heating. Underfloor heating is well known as the optimal heating option for indoor thermal comfort; however, it takes more time to reach the target room temperature, compared to heating via air or radiators. The TDM technology quickens that process by operating the Air-to-Air indoor units at the first stage of the heating process and will continue with the underfloor heating operation. The graph below shows the results of an internal Samsung lab test to compare pure Air-to-Water operation with the TDM Plus operation. The time needed to increase the room temperature from 5 degrees Celsius to 20 degrees Celsius is represented here. Pure Air-to-Water heating takes a very long time to reach a room temperature from 5 degrees Celsius to 20 degrees Celsius (approximately 400 minutes) compared to the TDM Plus operation, which takes approximately 50 minutes.

Simultaneous control for different Air-to-Water temperature zones
Our wired controller allows the user to simultaneously control two Air-to-Water zones with different temperatures. The user can set the temperature of the water supplied to each zone independently, and this will be used as the thermal ON/OFF factor. Alternatively, the target room temperature can be used as the control factor to determine whether cooling or heating demand occurs from a zone. However, the target operation parameter for the outdoor unit in Air-to-Water mode is the leaving water temperature. Therefore, what we at Samsung call a “Water Law” needs to be created for each zone: when there is a demand based on room temperature, the heat pump will operate in Air-to-Water mode by using the target water temperature set by the Water Law.

By turning on a setting called Water Law, the supply water temperature is set automatically based on the outdoor temperature, which is related to the cooling and heating load of the space. This saves energy, compared to a flat Water Law where the supply water temperature is fixed. Two operation lines, one per zone, have to be defined by means of the field settings. Each of these lines represent the relationship between the target water temperature per zone and the ambient temperature that is measured by the outdoor unit. In case of non-simultaneous demand from the two zones, the system operates according to the corresponding operation line. For example, in case only underfloor heating demand occurs, the leaving water temperature from the hydro unit is set according to the lower temperature line, and the mixing valve will be 100% open.

The Water Law values are controlled slightly differently during simultaneous operation of the two zones. The most unfavorable Water Law determines the target leaving water temperature of the hydro unit, which refers to the fan coil units/radiators water temperature in heating. The mixing valve will be operated to meet the target water temperature of the second zone, according to the set temperature difference with the most unfavorable Water Law.

About Samsung Electronics Air Conditioner Europe B.V. (SEACE)

Since introducing its first air conditioner in 1974, Samsung Electronics has been redefining indoor climate comfort for tomorrow’s society. For every space where people create memorable experiences together, be it commercial spaces or residential homes. At Samsung, we go beyond convention, through a relentless focus on pushing the boundaries of technology, innovation and design.
Samsung Electronics entered the European market of commercial air conditioning in 2005. Due to rapid growth and in support of its long-term commitment to the European market, Samsung Electronics Air Conditioner Europe B.V. (SEACE) was opened in 2017 in Amsterdam, the Netherlands. SEACE aims to harmonize the activities across more than 30 European countries. SEACE offers ongoing technical training in climate and smart building solutions; after sales and technical support for its industry partners; backed by Samsung’s quality reputation and leading-edge innovation, including digital connectivity solutions. SEACE thrives to fulfil the needs of its European markets including for both the commercial and residential market with innovation cooling, heating, domestic hot water, refrigeration and smart building solutions.