As central heating developed and developed
The history of centralized heating (CO) has counted more than 100 years and throughout this time it is continuously evolving.
The first water-based centralized heating distribution systems were put into operation in 1880 in the United States. These systems are known today as first-generation heating distribution networks (1G). Until the 1930s, steam steam was the only coolant.
In the 30s of the 20th century, hot water became an alternative vapor solution: due to this, the temperature of the heat carrier was reduced from 200 oC to 120 oC – and this innovation marked the beginning of the Second Generation (2G) in the history of the CO.
At this time, in Denmark, the first batteries of thermal energy (capacities) appear – as an integral part of the system of CO. First of all, this provided a great deal of flexibility in the work of the thermal power plants, which produce both heat and electric energy.
The next jump in the development of the technology of the CA system occurred in the early 1980s, when heat-insulated steel pipes came in the steel pipes in the ferro-concrete channels in the distribution networks of the CO.
This is how the Third Generation CO (3G) appeared – due to the transition to process pipes, thermal losses decreased and, as a consequence, it was possible to lower the operating temperature in the heating networks. Also, its contribution to the production of thermal energy began to bring renewable energy: due to the partial replacement of fossil fuels with the potential of biomass and the launch of large solar thermal power stations, which give excess heat in the network of the CO.
Such plants, based on the use of biomass and sun energy, are becoming more and more every year – in many countries around the world. The temperature of the heat flow in the networks gradually decreases to a level of 70-90 o C.
Today we are dealing with the Fourth Generation (4G), whose characteristic is the operating temperature of 50-60 ° C. Such a low heat carrier temperature is a consequence of the evolution of technologies that allow a significant reduction in thermal losses in the networks of CO.
At the same time, this is confirmed by the equally important fact: the use of a low-temperature resource makes it possible to use the excess heat industry, which until recently was only possible to write off for inevitable losses. Moreover, the volume of utilization of solar heat has increased due to the large seasonal storage of heat energy – for subsequent use in the winter.
The temperature of the fourth generation heat of 50-60 ° C is low, but recent test distribution networks of heating have confirmed their efficiency of operation, even at 30-35 ° C, thus, it is still too early to set a point in the history of the development of centralized heating.
Universities in the United States and Canada change their network of CEs – switch from steam (1G) to hot water (3G), and this will reduce existing heat losses by 33 – 50%;
In Copenhagen, Denmark, the last of all known steam systems of the CO, put into operation in 1906, is transferred to another coolant – hot water. In 2021, this project must be successfully put into operation – in this way a complete transition of the CO system from 1G to 3G will take place;
Thermal Power Plant in Copenhagen
In Albertslund, Denmark, recently began the development of the first project for the integrated translation of the municipal system of the 3rd Generation 3G – 4G. The opening of the facility is scheduled for 2026;
The current trend is shifting the TS system into an old third-generation housing stock (3G) into the fourth 4G.
It is important to understand the irreversibility of the evolution of the systems of the First or Third Generation COs – on the Fourth. A successful guarantee can be the fruitful communication of power industry with politicians and society, informing about the necessity of efficient use of “surplus” energy resources, which would be impossible to utilize without an existing centralized heat supply system.