Study of the Efficiency of Heat-Supply Systems with Steam Turbine CHP Plants, Taking into Account Changes in the Temperature of the Delivery Water during Transportation

The aim of the work is to study the efficiency of steam turbine CHPPs in heat-supply systems, taking into account changes in the temperature of delivery water during transportation for vari-ous initial and extended heating regulation schedules. To achieve this goal, the following tasks were solved: calculation of the dependences of the delivery water cooling in the supply and re-turn pipelines on the air temperature, construction of temperature and flow rate schedules of de-livery water adjusted for heat losses during transportation, calculation of energy efficiency indi-cators for the operation of a model CHPP with various options for correcting schedules of deliv-ery water. The most significant results are the following. Firstly, for the first time the method of the degree-by-degree calculation of heat losses during transportation and their distribution be-tween pipelines of heating networks was used. Secondly, the dependences of the delivery water cooling in these pipelines on the outside air temperature are calculated. Thirdly, it has been es-tablished that the specific reference fuel consumption for electricity supply significantly de-creases when switching to more efficient temperature schedules for heating regulation, but changes slightly when switching from natural regulation by flow rate to regulation by the tem-perature of the delivery water. The significance of the obtained results lies in the possibility of their use for an accurate assessment of the efficiency of heat supply systems with different heat-ing control schedules and for determining the feasibility of correcting temperature schedules in order to take into account the cooling of delivery water during transportation

Efficiency of Using Built-In Bundles of Cogeneration Steam Turbine Condensers for Make-up Water Heating

The purpose of the study is to determine the conditions and efficiency of the use of built-in bundles of condensers of cogeneration steam turbines for make-up water heating during their work when the main bundles are disabled. The proposed method for estimating the heat flows entering the condenser when working with a closed sliding grid is used. The program of the thermal calculation program for steam turbine condensers and a computational mathematical model of a turbine plant type T-50-130 are applied. The heat fluxes entering the condenser were calculated in a wide range of influencing factors. An important result of the calculations is the identification of significant limitations of the applicability of this method of the make-up water heating according to the condition that the temperature of the make-up water at the exit from the built-in bundle is not exceeded. Calculation studies on the mathematical model of a condenser to determine the pressure in the condenser depending on the pressure in the lower heat extraction section with different levels of throughput of the closed sliding grid and different flow rates of the make-up water were carried out. Another result is a calculated estimate of the energy efficiency when using built-in bundles for heating the make-up water. It was found that heat saving in the considered modes always takes place, and when working on a heat mode, it is close to the heat load of the built-in bundles, and when working on an electric mode, it is several times lower

Energy and Economic Efficiency of Gas Turbine Units and Heat Pumps in Power-supply Systems in the Arctic Regions of Russia

Currently, in publications, there is some controversy about the efficiency of various power-supply systems operating in extreme climatic conditions. The need to dispel this controversy explains this study's relevance. The purpose of this study is to evaluate the feasibility of the use of cogeneration gas turbine and microturbine units as the heat-and-power source for a camp-like residential facility in the Arctic regions of Russia. A boiler plant and a heat pump system are analyzed as heat sources for the afore-mentioned camp. The authors used their own mathematical models of the units to do the study. The estimates were based on the annual facility-specific power and heat consumption data, additionally climatic conditions and fuel kind (natural gas) were taken into consideration. The study resulted in defining the plants' limits of equal fuel consumption, depending on the substituted power output efficiency and the power/heat production cost to the price of gas correlation. Another result was the evaluation of the power efficiency (by the natural gas consumption) and economic feasibility, as well as the payback term. We concluded that in case the natural gas was the only fuel available the ground source vapor-compressing heat pump systems were power-wise and economically unsound, provided they were operated under environmental conditions typical for the Russian North and according to the region-specific heat-supply schedule. The outcome of this study can be used when planning/designing the power-supply facilities in extreme climatic conditions, as well as in evaluating/estimating the power-supply systems' efficiency

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Efficiency of the Operation of the Cogeneration Steam Turbine Plants at theVariable Heat and ElectricLoad Schedules

The urgency of the work is conditioned by the need to improvethe management methods of the operation modes of the power plant by creating software tools for predicting the performance of equipment when the conditions of its operation change. In this regard, the aim of the study is to carry out a detailed calculation research of such modes using uniquecomputational mathematical models based on the actual turbine power characteristics. Following tasks were set to achieve it: first, to calculate the limits of change for the main energy and economic indicators in real operating conditions on the example of the turbines T-50-130 of the Kirov CHP-4; secondly, to identify and describe the possible resources to increase the efficiency of the operation of the cogeneration turbine plants under conditions of variable heat and electric load schedules. The received results testifythat at today's prices for energy carriers, additional power generation by the thermal cycle of CHP plants is economically feasible during all day. The low economic efficiency of some common methods of generating peak power is shown, in particular, by changing the degree of opening the sliding grids in the low-pressure section. The proposed approach can be implemented and used to optimize the operation of CHP plants in the Russian wholesale electricity and capacity market. The results of the study make it possible to conclude that most steam turbine CHP plants have significant reserves for saving fuel and energy resources, which can be realizedby optimizing turbine operationmodes