Optimization of the heat release regulation system

Heat supply regulation should ensure high energy efficiency of district heating systems (DHS) in general, reducing the specific indicators of heat production and release and maintaining the normalized thermal regime of the premises with any changes in outdoor temperature, insolation, infiltration and heat. Usually the processes of central regulation of DHS at heat sources and heat consumers are considered separately: not only technically but also organizationally. In this regard, the proposal for joint consideration of central and local regulation of heat supply is relevant and useful. The proposed solutions can increase the efficiency of existing DHS at the stage of transition to modern options for their implementation, in which heat control units are located at the entrance to individual apartments, and thus, the degree of regulation of DHS as close as possible to autonomous heating systems. The purpose of the study is to comprehensively consider the impact of individual stages of heat supply on the overall efficiency of DHS. The most common in domestic DHS is a method of high-quality central control of heat supply by changing the temperature of the coolant in the pipelines of thermal networks at the outlet of heat sources. However, this method has a significant disadvantage - it is inefficient regulation during the period of cutting the temperature schedule with a joint load on heating and hot water. Working during this period leads to significant overheating in premises and unproductive heat loss. Unproductive heat losses because of inadequate regulation when lowering the heat release schedule reach up to 18% of the heat potential of the fuel used. The introduction of a combined quantitative and qualitative regulation is proposed, in which, up to the cutoff temperature of the temperature schedule, the heat release is controlled by changing the temperature of the coolant, and after the cutoff, the transition to quantitative central regulation is carried out. Practical recommendations for the implementation of such regulation have been developed. Combined central regulation ensures the possibility of providing hot water supply services throughout the entire heating period, avoids hydraulic and thermal deregulation of systems and ensures optimal conditions for the operation of heat generators, reduced energy consumption and a significant increase in the overall efficiency of the DHS. Key words: heat supply, centralized systems, energy saving, efficiency, heat load regulation

Evaluation of the effectiveness of the building heating control system

Currently, improving energy efficiency and introducing energy-saving technologies is a strategic task for all national economies. Improving the efficiency of buildings and reducing energy consumption in homes can lead to real reductions in resource consumption while ensuring the required level of living comfort. The use of different types of regulation of the building heating system allows the heat transfer of heating devices to be as close as possible to the current heat demand of the object in order to maintain the required internal temperature with a constant change in external conditions. The paper considers the following types of regulation: room-byroom regulation, regulation according to the temperature schedule of CHP and weather regulation. A calculation of each type of regulation was carried out and comparisons of room-by-room regulation with regulation according to the temperature schedule of CHP plants and with weather regulation were presented. As a result, the most effective option was proposed.

TO SETTING UP WEATHER REGULATORS FOR THE TEMPERATURE REGIME OF BUILDINGS

В работе рассматривается задача настройки импульсных погодных регуляторов, рекомендуемых для исключения «перетопов» зданий при избыточной мощности систем отопления как при «плохом» температурном графике, так и в период его «срезки», а также и при некачественной настройке нерегулируемых узлов смешения. The paper considers the problem of adjusting impulse weather controllers, recommended to avoid overheating of buildings with excessive heating systems power, both with a “bad” temperature schedule, and during its “cutoff”, as well as with poor tuning of unregulated mixing nodes.

STUDY OF THE HEAT-CARRYING FLUID TEMPERATURE INFLUENCE IN THE HEAT SUPPLY SYSTEM ON THE INDOOR AIR TEMPERATURE

This article presents a brief history of the country’s heat supply system development. The types of heat supply systems are considered, their brief characteristics are given. Methods for determining the heat load for household needs (heating and hot water supply) of urban residents are presented. The study of the coolant temperature influence on the air temperature in the room was carried out. The study used an experimental-theoretical research method. As a part of the experimental study, the data of temperature measurements in one of the heating points in Tyumen were requested. Within the framework of a theoretical study, the air temperature in a living room was calculated, depending on the coolant temperature according to the schedule of the CHPP and according to the supply in the supply heat pipe. In carrying out the theoretical study, standard methods were used for carrying out thermal calculations of heat supply systems, statistical research methods, as well as standard computer programs. The need to regulate heat energy is determined and the types of regulation are considered. The analysis of the adopted temperature schedule of the CHPP was carried out and a comparison was made with the calculated temperature schedule. The solution of the equation for determining the air temperature in the room is given. The air temperature in the room depends simultaneously on two factors: the temperature of the heating medium and the temperature of the outside air. As a result of the study, the presence of a discrepancy between the temperatures of the network water supplied to consumers and the created air temperature in residential premises was determined. The intersection point of the calculated temperature schedule and the CHP schedule was determined. The necessity of observing the calculated temperature schedule of the central quality regulation has been substantiated. The necessity of heat supply at a constant flow rate of the heat carrier has also been substantiated.

Increasing the efficiency of the thermal power units at zoning of heat load curve

The article deals with the work of heat and power units of thermal power plants in the conditions of disaggregation of the heat load schedule. The purpose of the work is to increase the efficiency of operation of CHP units operating under the conditions of the zoned temperature schedule. To achieve the obtained results, mathematical modeling based on the methods of differential-exergetic and thermodynamic analysis; methods of material, energy and exergetic balances. Research has shown that in order to increase the efficiency the original method of splitting the temperature graph into three zones can be used, each of which is characterized by the method of regulation of heat supply, and to assess the effect of the minimum fuel consumption criterion can be used. The method of determining the equivalent design temperature, which takes into account the regime peculiarities of heat and power units in the form of a method of regulation of heat supply, is developed. Study has shown that three design points should be available when zoning the temperature schedule. Based on optimization calculations for standard sizes of heat and power units of a wide range of capacities, the calculations show that the optimal parameters of heat and power units in the conditions of zoning of the temperature schedule as a whole correspond to the standard values. In addition, it is shown that in each zone of the temperature schedule there is a saving of fuel, which can be from 3 to 30% depending on the type of power unit, its capacity and zone of the temperature schedule, and the annual fuel consumption of the heat and power units can be reduced by approximately 10%. It is shown that when conventional power units operate according to the zoned temperature schedule and in the first zone (quantitative regulation), preference should be given to power units with steam production. In the second zone (mixed regulation), the operation of power units with steam extraction and heat and power units is equivalent. In addition, in the third zone (qualitative regulation) preference should accrue to heat and power units.

A cluster controller for transition matrix calculations

We demonstrate that a temperature schedule for single-spin flip transition matrix calculations can be simply and rapidly generated by monitoring the average size of the Wolff clusters at a set of discrete temperatures. Optimizing this schedule yields a potentially interesting quantity related to the fractal structure of Ising clusters. We also introduce a technique in which the transition matrix is constructed at a sequence of discrete temperatures at which Wolff cluster reversals are alternated with certain series of single-spin flip steps. The single spin-flip transitions are then employed to construct a single transition matrix.