The capacity of the heating system is calculated originally for the regime corresponding to the minimum outside air temperature, but how many days in the year would have this temperature? The maximum is a week, and the rest of the time the outside air temperature is higher than this. Then why do we run the boiler with maximum performance and burn so much fuel if its capacity exceeds what is required at those times? In order to save fuel, three- and four-way mixers are installed and they are connected to the automatic regulation system. Smart programmed equipment using temperature sensors on the pipelines of the warmth carrier and sensors of outside air temperature regulate the boiler’s work and each heating ring.
To automate the work of the system, an outdoor sensor is used which detects the outside air temperature and sends data to the controller. A special program with «temperature curve» is integrated into the controller. The values of the supply of warmth carrier, in accordance with the outside temperature are set in this program. The user simply chooses one of several temperature diagrams and the controller will send impulses to the burner of the boiler, regulating the height of flame in the burner. For example, on the coldest day — let’s say -30 degrees C — it is necessary to provide an average water temperature of 60 degrees C in the supply line. Then the diagram of the warmth regime is chosen in which the temperature curve goes through the point of crossing +60 degrees for water and -30 degrees of frost. Another fixed point of the temperature diagram: 20 degrees of warmth carrier and 20 degrees of outside air temperature (it is considered that at this point you do not need heating). By programming such a diagram you can be sure that on any other day of the year the system will change the temperature of the warmth carrier according to warmth demands for each individual day. If the house is poorly insulated or there are not enough radiators installed, a steeper dependence is chosen, so that the temperature of the warmth carrier will be not 60 degrees C but 80 degrees, when the outside temperature is -20. All the sensors of the heating system are connected to the controller and because of them, it manages the boiler and each secondary heating ring.
How can the system be managed without a controller? Suppose someone forgot to close the windows in the house and the temperature in a room served by one of the secondary rings plummeted. The sensor of the heating system mounted on the mixer registers a higher warmth output (because of sharp decrease of water temperature in the mixer) and sends a command for warmth from the primary ring. As you have probably realized, the heat demand opens a three- or four-way mixer for the secondary ring. The circulational pump starts to run water in the contour but it cannot raise the temperature and throws excessively cooled water into the primary ring which goes to the return pipeline of the boiler. The sensor which measures the temperature of the warmth carrier in the boiler, «reads» the lowered temperature, and increases the height of the flame in the boiler burner. While using the controller, almost the same thing happens, but faster. The sensor on the heating system detects a demand for warmth by the secondary ring and «tells» it to the controller and the controller, according to its program, sends a command to the burner of the boiler to raise the flame of the burner and to the mixer of the secondary ring, opening it. Moreover, it does so not simultaneously, but in accordance with the predetermined program to raise the air temperature in the room in a less noticeable way. In another situation, for example, if there are a lot of people in the house, the internal air temperature is increased, the controller detects the mismatch between internal and outside air and decreases the power output of the boiler. In other words, whatever is happening in the house, the controller keeps track of all the changes and adjusts the system in such a way to maintain a constant microclimate and people will not notice if there is frost outside or if it has become warmer, even if they forgot to close the windows — or the opposite, if other sources of heat appeared in the house.
For the heating schemes in Figures 54–58, both types of automatics can be used: the simple one using only sensors, or a more complex one, using a controller.
Simple automatics is reduced to the installation of three- or four-way mixers of servodrives, controlled by the sensors installed on the heating system pipes. The management of speed of the work of the circulational pump can be done manually, and the management of the boiler is done by its own automatics. This management scheme is quite viable and is not too expensive. In fact, its adjusting is reduced to simultaneous installation of the equipment and adjusting the speed of the pumps. In addition, each heating device (radiator) in the house can be equipped with a thermoregulating valve.
Usage of controllers is a more expensive variant but all the management is performed automatically. Manual tuning of the heating system can be done from a remote control which is located in one of the rooms of the house. Moreover these automatics permit management from the remote control, a computer, or a cell phone. For example, when you travel to your suburban house, you can send a command from your cell phone to the controller and when you get there, you see that the controller has warmed up the rooms (which were left in an economical heating regime) and also heated the banya.
You can buy an automatic system (see Figure 68) in one package with installed hydrocollectors, mixers, and pumps. Such systems are called «mounted heating modules». For example, the module «Hydro-Compact» (see Figure 58), which is mounted on a supporting steel frame, is a ready-made hydro unit for quick and easy installation of an energy saving boiler room, with a capacity up to 50 KW for a private house.
The module is equipped with two pump mixing groups and a built-in automatic weather dependent control. Servodrives and sensors are connected to the controller. Temperature diagrams, time programs, and contour parameters are integrated into the program of the controller. After the purchase and installation of such a module, the boiler, hot water heater of indirect heating of hot water supply, setting of radiator heating, and setting of warm floor heating are connected to it. The outside temperature sensor which comes in the package should be installed on the northern or northeastern wall of the house, away from windows and doors, protected from the sun and precipitation. The boiler sensor is immersed in a sleeve in the boiler unit. The module for controlling room air temperature should be installed in the room at a height of 1,5 m above the floor, far from the heating devices and parasitic heat sources. In the box of the controller there is a circuit breaker for connecting the power supply of the boiler.
The automatics of the module allow the management of two burning stages and the boiler’s working thermostat in this case is set to the value 85-90 degrees Celsius. The boiler pump, also known as the pump of the primary ring, also known as the collector pump, is connected either to the automatics of the boiler or to the automatics of the module, and for this connection a special terminal block is located on the module.