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How to integrate a heating and cooling system

Thanks to the TELETASK solutions, the control of a heating/cooling system is much more intelligent than with a conventional system. A TELETASK installation offers powerful integration for heating, cooling and ventilation. Thanks to this integration it becomes simple to automatically switch off the heating/cooling in a room when somebody opens a window or the access control system detects that people are coming home and the heating/cooling system is set to the comfort level…
TELETASK possibilities are only limited by your own fantasy.
Because there are so many different cooling and heating systems on the market, it is not always easy to integrate these systems with a general home automation system. TELETASK developed several products and solutions which allow to integrate close to every system available on the market. Thanks to a wide product range, the user can control the integrated system automatically, from standard push buttons, special touch panels, special touch windows, prestigious touchscreens, by remote control, by mobile telephone, via local computer on wired or wire-less Ethernet or even remote through the internet.
The user interfaces are not described in this chapter, but below, the different steps to set up this integration are described more in detail.
Details of the different components are also to be found in the data sheet of the concerning components or elsewhere in this handbook in the 'Sensor Functions' in the 'Functions' chapter.

HVAC Principe Schema V02

The basic operation of a heating/cooling control

Important: the explanation below is done for one temperature zone. Your project may have several heating and/or cooling zones.

Example: If you have different temperature settings in room x and in room y, you will have two temperature zones.

The basics of temperature control explained below are to be considered per zone. You can have as many temperature zones as the maximum available on the central unit in your project.

When you have a heating and/or cooling system integrated in your TELETASK domotics system, the basic operation is always the same:

  1. The TELETASK system measures, with its temperature sensor, the actual temperature in a room.
  2. In the TELETASK system the measured actual temperature is compared with the temperature which was set (is the target) by the user.
  3. If the actual temperature is lower than the target temperature, than the internal TELETASK heating control system will control the heating system to increase the temperature in the room. (Closing the Relay of the Heating system is the simplest way of control, but TELETASK has more intelligent control algorithms available).
  4. Time after time, the actual temperature is measured. The TELETASK system decides as soon as the target temperature is reached, to open its output contact again, so the heating system is deactivated.

In case of cooling, the control works the same way, but then about decreasing the temperature instead of increasing.
Anyhow, the basic operation is always like above. It only differs in controlling the output. The output control algorithm may be more complex (pulse with modulated output control with predictive algorithm, analogue control, multi-speed fan control…), but the basic operation is always about comparing the actual temperature with the set temperature.

The available internal temperature control algorithms

Heating

There are five different control algorithms defined in the TELETASK domotics system. Depending on the type of heating system, you will have to select one of the available algorithms in the control menu.

Standard
this is the most basic algorithm for temperature control. The heating output relay is switched on/off when the actual temperature and the set temperature become equal: the output relay contact is opened. When the actual temperature becomes lower than the set temperature: the output contact is closed again. This output contact can be used to control a valve, a fan or a circulation pump.
Air
this control algorithm is selected when you want to integrate a fan controlled heating system in a more intelligent way. In this case the TELETASK system uses a pulse width modulation method to control the connected fan. A cycle time of 10 minutes is used. Depending of the difference between the actual and the set temperature, the fan will be activated longer or shorter. This time is also depending on the Temperature. 10Volt = 100% time setting.

Example: The parameter is set to 5°C/10V and the difference between actual and set T is 3°C. Than the heating time will be 6 minutes (3/5 of 10 minutes). After 10 minutes, the difference in temperatures is measured again and a new cycle time is calculated and will be used in the next cycle.

Radiators 15min
this algorithm is to be selected when you use a heating system with wall mounted (water) radiators of the 'high yield' type. The algorithm works like the 'Air' algorithm, but with a cycle time of 15 minutes.
Radiators 20min
this algorithm is to be selected when you use a heating system with traditional cast iron (water) radiators. The algorithm works like the 'Air' algorithm, but with a cycle time of 20 minutes.
Floor heating
This is to be used when the output has to control a floor heating system. The algorithm is the same as above, but with a cycle time of 30 minutes.
Important: the slower the heating transfer process of your system, the longer the cycle time needed.

Cooling

For cooling, the three control algorithms which are available are 'Standard', 'Air 10min' and 'Air 15 minutes'. The working is equal to the heating algorithms above. The only difference is that the output is activated when the measured temperature is too high instead of to low.

In practice

These algorithms and their parameters can be configured in the following way:

  • Click 'Options' in the PROSOFT menu bar
  • Click the 'Sensor' tab.
  • Define the different parameters
  • Click 'OK' until you are back in the main PROSOFT window.

Setting up the output control of the heating/cooling system

How To Integrate A Heating And Cooling System 01
It is not defined by the control algorithm which output components are used for the output and to control the connected heating system, because there are a lot of different heating/cooling systems. On top of this, every heating/cooling system is different. Therefore, the used components of the TELETASK system have to be selected, linked with a temperature zone and the connected parameters are to be set. How to set this relation is described in the 'Analogue input interfaces' chapter in this handbook.

A practical example

The family Jones made a wise decision and decided to install a TELETASK system in their house. They also understood that the integration of the heating system was not an option, but just one of the reasons why you should install a home automation system. They have four temperature zones: the ground floor, first floor and two bath rooms with separate temperature settings. Every room in the house is equipped with radiators. The distribution of the hot water is done with four electromagnetic valves (open/close). There is one main water circulation pump.

Needed TELETASK components

  • 4 TELETASK temperature sensors (to be mounted on the best place and on the correct height)
  • 4 electrical zone valves (not from TELETASK) connected to four relay outputs of the TELETASK system.
  • 1 circulation pump from the heating system which is connected to an output relay of the TELETASK system.
  • 1 touch panel (or more) with a display for temperature control.
Remark: the circulation pump will be ON as soon as at least one valve is OPEN. As soon as all valves are closed, the circulation pump is to be stopped, to avoid unnecessary energy consumption.

In practice

  • In PROSOFT go to the 'Extra' 'Options' 'Sensors' menu and select the 'Radiators 20 min' control algorithm.
  • In PROSOFT select the desired output unit and define each output relay for the sensor zones which will have to control one of the four valves of the heating system (for example relay output 1, 2, 3 and 4). So you will have to enter the names of the four zones in the relay name fields (relay 1: 'ground floor valve', etc…
  • Define the relay which is to control the circulation pump (for example R 5) and add the name 'main circulation pump'.
  • Go to the analogue input interface on which the T sensors will be connected and define a first T sensor and give him the name 'Ground floor'.
  • In the Properties menu under the tab 'Heat' enter as control method 'standard relay'.
  • Select in the On/off field the relay for valve control of the ground floor (R1 in this case).
  • Enter the temperature settings for day, night and standby preset. These can always be changed by the user.
Remark: The frost protection is a general parameter which is the same for all temperature zones. You can set this parameter in the 'Extra' 'Options' 'Sensors' menu. Standard this parameter is set to 5°C.
  • Repeat this for the other three temperature sensors.
  • Now make a condition function 'Heating ON' wherein the valves of the different T zones (R1, R2, R3 and R4) are all noted with an 'OR' relation between them.
  • Make a process function which guards the condition function 'Heating ON' (=ON) 'continuous monitoring (ON and OFF)' and which controls the circulation pump (R5).
  • Select this process function in the 'auto start' function: in PROSOFT main window, select 'Extra' 'Options' 'Option' and you will find the 'automatic start function' field there in the 'Service options'.
  • The whole heating system is now integrated and ready to be started.

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