Water heating is the most universal and widespread technology. The use of water as a heat transfer liquid is conditioned by its high heat holding capacity. Although, the use of antifreeze (antifreeze) is becoming more common, which prevents damage to the system when the coolant freezes.
In water heating systems, you can use different (even within one system) heat sources:● gas boiler● solid fuel boiler● electric boiler● heat pump● fireplace with water heat exchanger
For direct heating of premises are used:● radiators (cast iron, steel, bimetal)● contours of a heat-insulated floor● fan coils● heat exchangers for separation of the heat carrier of a boiler and the heat carrier of radiators
Various types of piping are used to ensure the transfer and distribution of the coolant from the heat sources to the heating devices.
Single-pipe (series) - easy to implement, cheap due to the minimum required materials. Among the disadvantages - uneven heating of radiators, it is impossible to adjust the temperature in each individual radiator.
Two-pipe (parallel) - connection of heating radiators is carried out by two pipes laid in parallel with the movement of water in the system. The advantages include the ability to quickly control the temperature, fast and relatively uniform heating of radiators, relative ease of installation.
Two-pipe (parallel associated, Tichelmann loop) - an advanced parallel connection scheme for radiators. Hydraulically balanced system with the lowest possible total resistance without the use of control valves. It can provide uniform heating of all radiators in self-flowing systems (without pumps) or with a small pump. The disadvantages are the large number of mounting materials.
Collector - heated water from the boiler is supplied to the distribution collector, which further distributes the coolant between the heating devices. Features - good appearance, centralized control of coolant distribution between radiators and underfloor heating. It is characterized by relatively high cost and the need to use additional devices for distribution and regulation of flows.
In addition, it is important to ensure constant and unimpeded movement of the coolant in the system in one of two ways:
Natural - the coolant rises from the boiler up the pipeline (due to lower density), gradually passes through all the radiators, where it is cooled, and returns to the boiler. For such a process, it is important to ensure a small but constant slope of the pipes.
Forced - by means of the circulating pump. There may be several circulation pumps in the system.
It is impossible to build an efficient heating system without additional devices to control heat distribution and automate their operation. Their purpose is to control the supply and temperature of the coolant in each heating zone.
Thermostatic valves, specialized controllers (thermostats) are used to automate the water heating system, or automation is provided by Smart Home system.
Necessary equipment for this:● air temperature sensors● coolant temperature sensors (control of boiler, collector, multi-way valves, underfloor heating circuits)● thermal heads/actuators (with mounting on the radiator or collector, normally closed or normally open, wired and wireless, in 2 positions or with smooth adjustment of the opening, with a supply voltage of 24V, 220V or with a built-in battery)●  circulation pumps (pump groups)● multi-way (three-, four-, six-way) valves for partial mixing of flows with different coolant temperatures (mandatory if the system uses both radiators and underfloor heating)