THE COMPARATIVE ANALYSIS OF AUTOMATIC CONTROL SYSTEMS FOR THE HEAT SUPPLY OF RESIDENTIAL BUILDINGS IN MONOTONOUS TRANSIENT PROCESSES AND IN PROCESSES RECOMMENDED BY REGULATOR MANUFACTURERS

Results of studies of the automatic regulation system of a residential complex along the street of Academician Sakharov in the city of Chelyabinsk are given in article. The analysis of actual indica-tors of volumes of consumed gas within several months 2015–2017 is carried out depending on average daily temperature of external air. It is shown that the adjustment of the controller by the factory method does not ensure the effective functioning of the heat supply system, especially at ambient temperatures close to 0 °C. The comparison was carried out in two ways: by the method of equivalent trends and by the average temperature and consumption of gas per month. The conducted analysis convincingly proves that the control system with monotonic processes is not only more effective from the point of view of the operation of the equipment, but also from the point of view of energy efficiency.


Introduction
For three years, studies were carried out to optimize the regulation of the heat supply of the residential complex by automatic means. In March 2016, in the system of automatic regulation of a residential complex along the street of Academician Sakharov in the city of Chelyabinsk. After the studies, parameters of the ECL Comfort 200 controller were installed, providing monotonic transients without oscillation. In May 2017, the volume of gas consumption was analyzed in the automated heating system of this residential complex. The results of optimization of the coolant temperature control processes are shown in the paper [1]. It is shown how the amplitude and the period of self-oscillations of the controlled temperature are significantly reduced from 10 °C for a period of 30 minutes to 1 °C for a period of 5 minutes (Fig. 1, 2).

Statement of the problem
At the same time, despite the obvious advantages of monotonous transient processes, due regard is not paid to their tuning, since fluctuations in the temperature of the coolant are not noticeable to the consumer, and direct saving of resources is not obvious at the same time. The latter is due to the fact that in the theory of automatic control of heat supply systems there is an idea of processes as processes in linear or close to them systems. So most often the object of heating is represented by a combination of links of lag and inertia [2]. In such a system, oscillation is not a sign of an increased consumption of resources. In addition, the documentation for regulators [3,4] states that oscillatory processes are normal regulation. In the course of experiments with the control system conducted at the individual heat point of the house in February 2016, parameters were established to ensure practically monotonous control processes.

THE COMPARATIVE ANALYSIS OF AUTOMATIC CONTROL SYSTEMS FOR THE HEAT SUPPLY OF RESIDENTIAL BUILDINGS IN MONOTONOUS TRANSIENT PROCESSES AND IN PROCESSES RECOMMENDED BY REGULATOR MANUFACTURERS
sumption data are recorded by the operation services [5], and the temperature is taken from the Internet resource [6], which provides the weather archive to the weather station. The comparison was conducted in two ways: -Average temperature and gas consumption for a month; -The method of equivalent trends (the comparable charts reveal similar temperature trends (not less than 5-6 days) and gas consumption and determine the efficiency of resource consumption -for the same temperature or low temperature for the same consumption).
Throughout these methods, efficiency with monotonic processes is higher.  The tables show calculated "Heating coefficients", as the ratio of the volume of gas consumed per month to the average temperature on which the room was warmed -from the average outside air temperature to the average "comfortable" temperature -18 °C. As can be seen from the above results, this coefficient depends on the external air temperature. If the outside temperature is about 0°C, the coefficient is higher. This is explained by the fact that with the intensive operation of the control system, its efficiency decreases, and at low temperatures, when the operation of the heating system is required to its full capacity, its efficiency increases. There are no costs for regulating the supplied heat. This circumstance once again confirms the important role of the quality of automatic control processes in the operation of heating systems. In support of this provision, we will review the data on heat costs for 2015 and early 2016. In these months, the regulators worked with the manufacturer's recommended settings, i.e. with oscillatory processes (Fig. 1). At an air temperature of − 2 to + 2 °C, the coefficient is 32 and above, and at a temperature of −10 °C and below it is about 27. This shows the prospects in saving resources due to the quality of regulation of more than 20%. After setting the parameters of the regulators that ensure a minimum oscillation of the processes, these coefficients decrease, although the trend persists: at high ambient temperatures the coefficients are 25-26, and at low 29-30. The heating factor improved by 7-10%. This confirms the hypothesis of the energy efficiency of a regulatory system with monotonic processes, shows that the effect of improving regulatory systems can be even more significant, for which it is required to continue theoretical analysis and research.

Conclusions
Thus, the conducted analysis convincingly proves that the control system with monotonic processes is not only more effective from the point of view of the operation of the equipment, but also from the point of view of energy efficiency.