Improving a heat supply system by increasing the efficiency of the heat pump unit

The reliability and efficiency of the operation of district heating systems is largely determined by the efficiency of preparation of heating network water. In open heat supply systems, make-up water, among other things, compensates for the water intake in hot water supply systems. A number of technologies have been developed that increase the efficiency of an open heat supply system by reducing the water consumption in the supply pipeline of the heating network, increasing the operating time of the heat pump, and increasing the specific generation of electricity for heat consumption at the CHP plant due to additional cooling of the network water in the return pipe of the heating network.

Mobile Thermal Energy Storage

The article is devoted to topical issues related to the storage, accumulation and transportation of heat by stationary and mobile heat storage. Analysis of the current state of the district heating system indicates significant heat losses at all stages of providing the consumer with heat. The use of heat storage in heat supply systems leads to balancing the heat supply system, namely, the peak load is reduced; heat production schedules are optimized by accumulating excess energy and using it during emergency outages; heat losses caused by uneven operation of thermal equipment during heat generation are reduced; the need for primary energy and fuel consumption is reduced, as well as the amount of harmful emissions into the environment. The main focus is on mobile thermal batteries (M-TES). The use of M-TES makes it possible to build a completely new discrete heat supply system without the traditional pipeline transport of the heat carrier. The defining parameters affecting the efficiency of the M-TES are the reliability and convenience of the design, the efficiency and volume of the “working fluid”, the operating temperature of the MTA recharging and the distance of transportation from the heat source to the consumer. The article contains examples of the implementation of mobile heat accumulators in the world and in Ukraine, their technical and technological characteristics, scope and degree of efficiency. The technical indicators of the implemented project for the creation of a mobile heat accumulator located in a 20-foot container and intended for transportation by any available means of transport are given.

ENERGY EFFICIENCY OF COMBINED HEAT SUPPLY SYSTEMS

The consumption of energy resources in the world states is constantly growing from year to year. The production of fossil fuels is also increasing, but for various reasons it cannot fully cover the required amount from consumers. One of the most important consumption sectors is heat loads from heating, ventilation and hot water supply of industrial and residential buildings. To cover the thermal loads of heating and hot water supply, the necessary heat carrier is water heated to a certain temperature. The most promising from the point of view of heating water for hot water supply are solar collectors. Hot water for heating needs to be reheated practically throughout the entire heating period. The introduction of heat pumps is promising. When using solar collectors, the heating agent can be reheated in heat pumps. The aim of the study is to develop such a combined heat supply system that uses more renewable energy and as a peak source a fossil fuel boiler (electric energy), as well as a method for calculating this system to determine the optimal composition of equipment and rational modes of its operation. The methodology for calculating heat supply systems combining solar collectors, heat pumps and fossil fuel boilers is presented. The problem of load distribution between the main elements of the combined heat supply system should take into account the probabilistic component. This is due to the fact that with a changing real mode of operation, different thermal load of the equipment can be optimal. This is primarily influenced by the variable heat inputs from solar collectors during the day. According to the above method, it is possible to determine the optimal parameters of the heat supply system for different operating modes, at which the minimum consumption of fossil fuel will be ensured.

The Efficiency of Vapor Compression Transformation of Energy Flows for Heat Supply Based on the Sea Water

The results of the analytical study substantiated the operating conditions for the highly efficient use of the temperature potential of seawater in heat pump heating systems (HPHS) for buildings a building with correspondingly improved environmental indicators. Based on the analysis of the regional conditions of the Odessa water area of the Black Sea, the initial parameters have been substantiated and rational modes of operation of an improved HPHS with central, decentralized or local heating of the subscriber energy carrier have been determined. As indicators for evaluating the efficiency of the HPHS operation, the conversion factor of energy flows and the specific consumption of external energy for the drive of the compressor and the circulating pump of cooled water in the operation of heat pump units were considered. For seawater in the Odessa water area of the Black Sea during the entire heating period, the following temperatures were considered as initial data for analysis: water at the inlet to the evaporator (5–10) ° C, at the outlet (1 °C); calculated temperature difference of the coolant in the heating system (50–40) °C, indoor air (20 °C); estimated outdoor temperature (–18 °C). The characteristic correspondence between the flow rates of the cooled sea water and the heated energy carrier of the heat supply system was taken into account. The prerequisites of high efficiency of the heat pump heat supply system in which the actual conversion coefficient exceeds the seasonal normalized calculated and minimum value at an outdoor temperature of (–10) °C under the limiting conditions of the monoenergy regime for both new and reconstructed buildings were substantiated. In the course of the study, it has been determined that the total specific consumption of external energy for the compressor drive and the circulation of cooled water in the operation of a heat pump unit with a characteristic ratio of water equivalents, even under the limiting conditions of the monoenergetic mode of operation of the heat supply system at an outdoor temperature of (–10) °C, are within the range of generally accepted values (w = 0.28–0.34).

Adaptive control systems for marine thermal installations

В статье рассмотрен вопрос повышения точности и качества управления приводом сетевых насосов в составе судовых тепловых установок в системе отопления судна путем применения адаптивной системы автоматического управления. При использовании классических систем управления на основе ПИД-регуляторов для управления мощностью электродвигателя по критерию обеспечения заданного давления в системе теплоснабжения в условиях резкопеременных тепловых нагрузок могут возникать ситуации разрегулирования системы вследствии возникновения дополнительного давления в тепловой установке при термическом расширении теплоносителя. Для обеспечения надежности и безаварийности работы судовых тепловых установок при резкоперменных нагрузках авторами рассматривается возможность использования для управления мощностью электропривода адаптивной системы управления. В статье рассмотрена схема управления с адаптацией коэффициентов ПИД-регулятора на базе нейронной сети (нейросетевой оптимизатор). Нейросетевой оптимизатор был применен как надстройка над ПИД-регулятором в схеме управления мощностью сетевого насоса в составе судовой тепловой установки. Рассмотрены зависимости характеристик систем управления от структуры и параметров модифицированных критериев точности и качества управления. Адаптация параметров регулирования позволяет обеспечить достижение желаемых параметров с меньшими затратами мощности при сохранении уровня надежности и исключить разрегулирование системы управления при резкопеременных тепловых нагрузках. The article discusses the issue of improving the accuracy and quality of control of the drive of network pumps as part of ship thermal installations in the ship's heating system by using an adaptive automatic control system. When using classical control systems based on PID regulators to control the power of the electric motor according to the criterion of providing a given pressure in the heat supply system under conditions of sharply varying thermal loads, situations of system maladjustment may occur due to the appearance of additional pressure in the thermal installation during thermal expansion of the coolant. To ensure the reliability and trouble-free operation of ship thermal installations under abruptly variable loads, the authors consider the possibility of using an adaptive control system to control the power of an electric drive. The article describes a control scheme with adaptation of the PID controller coefficients based on a neural network (neural network optimizer). The neural network optimizer was used as a superstructure over the PID controller in the power control circuit of a network pump as part of a ship's thermal installation. The dependences of the characteristics of control systems on the structure and parameters of the modified criteria for the accuracy and quality of control are considered. Adaptation of control parameters allows achieving the desired parameters with lower power consumption while maintaining the level of reliability and eliminating deregulation of the control system at abruptly varying thermal loads.

Digital technological model of heat exchange control in an air heat pump in a low-rise building

The use of air source heat pumps together with other renewable energy devices and highly efficient heating equipment together with digital control systems is a promising European trend that continues to grow in the face of rising prices for traditional energy sources. The article presents a number of technical energy-saving solutions, such as a mixing chamber for HVH, built into the heat supply system and the use of a supply and exhaust ventilation system, in which the principle of recuperation is incorporated. A digital modular-functional-structural diagram of heat generation of a heat carrier from the environment is proposed. Relying on the energy efficiency of the circuit design with an electric boiler, a buffer tank and a patented mixing chamber, the authors achieve a rationally controlled heat and air exchange of a combined heat pump system for heating premises. Automation of the joint work of rationally selected elements of the heat pump air system is one of the Smart Home technologies that improve the efficiency of heat supply, create comfortable living conditions and safety through digitalization of the control algorithm for this system.

Visualization of physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB to diagnose the condition of external heat supply networks

Nowadays, Russia has the longest heating network system in Europe (about 125 000 km in total). Given the constant growth in the volume of construction space, the length will constantly increase. Consequently, there is a request to increase the level of reliability of heat supply networks. It is possible to satisfy the request only by increasing the volume and quality of comprehensive diagnostics of heat supply networks with simultaneous reduction of time costs. This is possible only if a new generation of measurement and computing complex (MCC) is developed for the diagnosis of heat supply networks. The team of authors examines the features of the information environment in heat supply networks, separately noting the possibility of switching the flow from single-phase to multi-phase and back. The paper proposes to consider a solution to a problem that arises when trying to visualize physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB. It consists in the fact that the desired physical and mathematical model should describe the thermodynamic processes of a single-phase flow, but taking into account that this flow moves in the external heat supply network. The possibility of using the MATLAB functional environment for developing a model based on visually oriented programming is considered in detail, which allows us to lay the foundations for further forecasting the development of the heat supply system.

Energy Efficiency of DH System with Wood Chips Boiler Houses and Flue Gas Condensing Unit

This study proposes a method for the evaluation of the efficiency of a heat supply system based on a correlation analysis of the data of the system's operations. The data from the system's operations have been analysed and a correlation equation has been applied to obtain the results of the analysis, which are then used for further calculations. The data can be divided into two groups: data characterising the condenser operations in the boiler house, and data characterising heating networks.

Improving the Efficiency of Autonomous Heat Supply Systems by Implementing Integrated Control Systems

In this paper we studied the actuality of the problem of optimal control of the heat supply system as a single complex object on the basis of a generalized mathematical model that takes into account the dynamics of the fuel combustion process, heat generation, its transmission through the heat network and that takes into account the dynamics of heat energy consumption and various external factors.