Heating Costs Research Articles

Simulation of demand response on buildings and district heating production

Demand response (DR) has effectively maximized renewable energies integrated into energy supply systems. This paper investigated DR benefits on three building types and the district heating (DH) production of a community consisted by these buildings in German conditions. Firstly, the buildings and the DH production were simulated without DR by tools IDA-ICE and HGSO, separately. Secondly, the three buildings were simulated by a rule-based DR control. After that, the tool HGSO calculated the total production costs and CO2 emissions based on the power demand with DR. The results show 2.8%-4.8% heating cost savings by DR for different building types. For DH producers, DR application reduces the total DH demand and CO2 emissions by 3.8% and 32.3 %, respectively.

STUDY OF THE INFLUENCE OF HYDRODYNAMIC AND STRUCTURAL PARAMETERS OF THE EXISTING HEATING SYSTEM OF THE BUILDING OF THE FIRST EDUCATIONAL BUILDING OF NULES OF UKRAINE ON INDICATORS OF COMFORT OF PREMISES

When assessing the thermal condition of the building and the parameters of the microclimate of the premises, the main factors influencing its thermal inertia were identified and taken into account. An assessment of the influence of the resistance of enclosing structures on the efficiency of the heating system, taking into account the influence of external and internal climatic parameters in the dynamic mode. It is shown that the time factor and depth of regulation, as well as the outdoor air temperature are important factors. Researches are carried out and the expediency of introduction of a duty mode of heating of buildings of HIGH SCHOOLS is estimated. The given algorithm of control of process of heat release (especially in the presence of a point of "breaking" - average (them) on the schedule) in addition increases accuracy of the decisions of the specified problems and reduces a temperature deviation by 4 ÷ 6 ° C in comparison with usual ("linear") dependence that allows to correct more precisely release of the heat carrier in system of heating of a structure at introduction of a standby mode. It was found that it took about 6.5 hours to achieve normalized air temperature and space heating in the forced (after a long stay on duty). It is shown that the heat consumption of the system in such conditions of its operation compared to the nominal mode increased by 25% (taking into account the limit value of the specific allowance from table H1 DBN B.2.5-67: 2013 "Heating, ventilation and air conditioning"), but for the entire period the action of the standby mode savings amounted to about 6-8% of energy consumed. Taking into account the design of the outer walls of the object of study, the temperature graph of the heating system was adjusted taking into account the value of the internal heat capacity of the building when implementing on-duty heating, which, according to preliminary estimates, will: improve comfort in the room; to reduce heating costs of the educational and administrative building of NULES of Ukraine by 10-12% for the heating period.

Learnings from experiments with MPC for heating of older school building

The paper presents the learnings from designing and running a model predictive control (MPC) of the heating system in a school building. Several real-life applications of MPC controlled heating have been presented in the literature. Most of them work by controlling the room temperature usingn a heating system and thus need a reference measured temperature in the building. Some have a single-zone temperature as the reference, while others use some kind of mean temperature of multiple rooms. In the present experiment, the MPC used the mean temperature of all rooms as the reference and was able to keep it within a lower and upper comfort bound, while minimizing the heat costs by responding to a heat price signal. However, the analyses of the temperature in each room revealed that the temperature bounds were heavily violated: some rooms were too cold and some too warm, while the mean was within the bounds. The main conclusion from the study is that, at least for buildings with different sized rooms and room radiator capacities, it’s not reliable to use a mean room temperature – rather, the control must consider individual rooms in order to guarantee comfort.

RENEWABLE ENERGY INTEGRATION FOR HOT WATER SUPPLY AND HEATING OF BUILDINGS

Solar energy is widely used in solar systems, where economy and ecology are combined. Namely, this represents an important moment in the era of depletion of energy resources. The use of solar energy is a promising economical item for all countries of the world, meeting their interests also in terms of energy independence, thanks to which it is confidently gaining a stable position in the global energy sector. The cost of heat obtained through the use of solar installations largely depends on the radiation and climatic conditions of the area where the solar installation is used. The climatic conditions of our country, especially the south, make it possible to use the energy of the Sun to cover a significant part of the need for heat. A decrease in the reserves of fossil fuel and its rise in price have led to the development of optimal technical solutions, efficiency and economic feasibility of using solar installations. And today this is no longer an idle curiosity, but a conscious desire of homeowners to save not only their financial budget, but also health, which is possible only with the use of alternative energy sources, such as: double-circuit solar installations, geothermal heat pumps (HP), wind power generators. The problem is especially acute in the heat supply of housing and communal services (HCS), where the cost of fuel for heat production is several times higher than the cost of electricity. The main disadvantages of centralized heat supply sources are low energy, economic and environmental efficiency. And high transport tariffs for the delivery of energy carriers and frequent accidents on heating mains exacerbate the negative factors inherent in traditional district heating. One of the most effective energy-saving methods that make it possible to save fossil fuel, reduce environmental pollution, and meet the needs of consumers in process heat is the use of heat pump technologies for heat production.

Study of a solar installation for olive mill sludge treatment

Olive mill sludge treatment was performed using a parabolic trough solar collector (PTC) to supply thermal energy. The proposed prototype, composed of a drying chamber coupled with a heat exchanger and a PTC, allows the treatment of up to 80 kg of wet olive oil pomace in about 1 hour and 40 min, the equivalent of 112 tons during the post-production period of olive oil. Due to the presence of oil, which delays evaporation, the drying process was studied at relatively high temperatures between 120 and 140 °C. The obtained results show that the effective diffusivities varied from 2.59 10−7 to 1.36 10−6 m²/s with an activation energy of 27.9 kJ/mol. The sludge dryer performance has also been analyzed and optimized numerically with MATLAB software. The indirect solar dryer using a PTC showed a relevant level of stability, fewer temperature fluctuations, and better control of the drying parameters compared to the direct solar dryer. The overall analysis reveals that the maximum thermal efficiency of 43% was recorded with total thermal energy produced throughout the year of 23,909 kWh, while the Levelized cost of heat was 0.34 $/kWhth. The proposed system leads to the avoidance of about 15,900 kg of CO2 emissions.

Process Modeling, Optimization and Cost Analysis of a Sulfur Recovery Unit by Applying Pinch Analysis on the Claus Process in a Gas Processing Plant

The Claus process is one of the promising technologies for acid gas processing and sulfur recovery. Hydrogen sulfide primarily exists as a byproduct in the gas processing unit. It must be removed from natural gas. The Environmental Protection Agency (EPA) notices that increasing SO2 and CO2 in the air harms the environment. Sulfur generally has an elemental content of 0.1–6 wt % in crude oil, but the value could be higher than 14% for some crude oils and asphalts. It produces SO2 and CO2 gases, which damage the environment and atmosphere of the earth, called primary pollutants. When SO2 gas is reacted with water in the atmosphere, it causes sulphur and nitric acid, called a secondary pollutant. The world countries started desulphurization in 1962 to reduce the amount of sulfur in petroleum products. In this research, the Claus process was modeled in Aspen Plus software (AspenTech, Bedford, MA, USA) and industrial data validated it. The Peng–Robinson method is used for the simulation of hydrocarbon components. The influence of oxygen gas concentration, furnace temperature, the temperature of the first catalytic reactor, and temperature of the second catalytic reactor on the Claus process were studied. The first objective of the research is process modeling and simulation of a chemical process. The second objective is optimizing the process. The optimization tool in the Aspen Plus is used to obtain the best operating parameters. The optimization results show that sulfur recovery increased to 18%. Parametric analysis is studied regarding operating parameters and design parameters for increased production of sulfur. Due to pinch analysis on the Claus process, the operating cost of the heat exchangers is reduced to 40%. The third objective is the cost analysis of the process. Before optimization, it is shown that the production of sulfur recovery increased. In addition, the recovery of sulfur from hydrogen sulfide gas also increased. After optimizing the process, it is shown that the cost of heating and cooling utilities is reduced. In addition, the size of equipment is reduced. The optimization causes 2.5% of the profit on cost analysis.

ЕНЕРГОСПОЖИВАННЯ НАВЧАЛЬНИХ КОРПУСІВ УНІВЕРСИТЕТУ В УМОВАХ КАРАНТИННИХ ОБМЕЖЕНЬ УКРАЇНИ

Target. To analyze the features of energy consumption of the building of the educational building No. 17 of the National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute" in the conditions of quarantine restrictions in the implementation of energy-saving heating schemes.Methodology. Dynamic energetic modeling of a university academic building created in the DesignBuilder software environment under normal and quarantine modes.Results. Recommendations for the implementation of energy-saving modes of heating the building of the academic building of the university during the period of distance learning when introducing quarantine restrictions in Ukraine.Scientific novelty. An integrated approach has been developed to an in-depth analysis of energy consumption under conditions of partial use of the premises of educational buildings during the quarantine period. It is substantiated that the use of premises with partial operation of the building requires additional unit costs for heating needs.Practical significance. Simulation dynamic modeling of the building's energy consumption for heating for various modes of operation and employment / use of premises of educational buildings during the quarantine period in Ukraine, the results of the study will allow to obtain a set of energy characteristics of the building as a whole and its individual rooms / zones for hourly changes in internal operating conditions and external climatic conditions. The use of the proposed scheme of operation of the heating system of the building of the educational building allows to reduce energy consumption during the heating period by 8,5% compared to energy consumption during normal operation, which is economically feasible in conditions of partial occupancy of the building during quarantine restrictions (during lockdown) and an unpredictable macroeconomic situation on the energy market, causing a trend towards an increase in prices for basic energy resources.

Who suffers from energy poverty in household energy transition? Evidence from clean heating program in rural China

It can be challenging to provide energy that is both clean and affordable. In northern rural China, a household clean heating program has been adopted, requiring households to transition from coal to electricity and natural gas. This program led to an unintended sharp increase in the burden of heating cost for enrolled households, even with large subsidies. To investigate this policy-induced increase in energy poverty, we conducted a large-scale household survey in northern China. We find that energy poverty, measured in multiple dimensions, is significantly increased by replacing coal with electricity and gas, while it is decreased by replacement with clean coal. Econometric analysis shows that the change in energy poverty is heterogeneous in several ways. It remains stable in Beijing, but increases by 70% in the much less developed neighboring province of Hebei. Households with lower income, less education, and smaller household size are more likely to experience energy poverty. Those with lower income and no insulation for their houses are negatively affected to a larger degree. These findings provide empirical evidence that a mandatory “one policy for all” is likely to hurt low-income households more. It calls the attention of policy makers to the distributional effect when designing energy transition policies for a clean and low-carbon economy.

On the influence of decommissioning an area thermal substation in a district heating system on heat consumption and costs in buildings – Long term field research

Modernization of the existing district heating systems is a necessary activity to improve their energy efficiency in the field of generation, distribution and use of the heat. This paper presents the results of several years of field research carried out for 13 multi-family buildings supplied from the district heating network. The benefits associated with the decommissioning of a bifunctional area substation and the use of compact heat exchanger thermal stations with weather automation in each analyzed building were demonstrated. The use of a weather controller in the area substation contributed to a reduction in the corrected heat consumption in a heating system by 23.6% the following year. As a result of the reconstruction of the area substation into individual stations in the buildings, the actual heat consumption for domestic hot water demand decreased by an average of 29% over 10 years, and the annual unit heat consumption for this purpose decreased by an average of 0.13 GJm−3. Considering the influence of the district heating system modernization on the corrected annual heat consumption for space heating, a reduction of heat consumption by 17.8% in the building B4, 20.4% in the building B7 and 23% in the building B13 was obtained.

Improving Thermoeconomic and Environmental Performance of District Heating via Demand Pooling and Upscaling

This study evaluates the effects of pooling heat demands in a district for the purpose of upscaling heat production units by means of energy, exergy, economic, exergoeconomic, and environmental indicators, as well as the sensitivity to investment and fuel costs. The following production systems to satisfy the heat demands (domestic hot water production and space heating) of a mixed district composed of office (80%), residential (15%), and commercial (5%) buildings are considered: gas- and biomass-fired boilers, electric boilers and heat pumps (grid-powered or photovoltaic -powered), and solar thermal collectors. For comparison, three system sizing approaches are examined: at building scale, at sector scale (residential, office, and commerce), or at district scale. For the configurations studied, the upscaling benefits were up to 5% higher efficiency (energy and exergy), there was lower levelized cost of heat for all systems (between 20% and 54%), up to 55% lower exergy destruction costs, and up to 5% greater CO2 mitigations. In conclusion, upscaling and demand pooling tend to improve specific efficiencies, reduce specific costs, reduce total investment through the peak power sizing method, and mitigate temporal mismatch in solar-driven systems. Possible drawbacks are additional heat losses due to the distribution network and reduced performance in heat pumps due to the higher temperatures required. Nevertheless, the advantages outweigh the drawbacks in most cases.

INDIVIDUAL DISTRIBUTION OF THERMAL ENERGY CONSUMPTION IN AN APARTMENT BUILDING: PRACTICAL EXPERIENCE

The cost of thermal energy production is constantly growing, on average, tariffs in the regions of Ukraine have tripled in recent years. The component of payment for heating in utility costs is the main one for most apartment buildings, but due to the peculiarities of district heating systems, residents do not have an impact on heat consumption, and there is a problem of uneven heat distribution: some rooms are overheated, others unheated. The normative documents of Ukraine indicate the installation of metering and regulation of energy consumption as one of the main measures to increase the level of energy efficiency of buildings. Modernization of heating engineering systems with the installation of thermostats and heat distributors is one of the most discussed energy saving measures at the general meeting of condominiums, which is of interest to most residents of buildings in operation. Experience shows that after the installation of such devices, the consumption of thermal energy by buildings is reduced, which leads to a reduction in heating costs.
 The relevance of the topic of this article is to study modern methods of individual distribution of thermal energy in apartment buildings, in particular in houses with a vertical heating system. The object of the study is an existing apartment building in Kyiv, where, starting in 2019, thermal energy distributors were put into operation. The subject of the study is the methods of heat distribution between apartments and the analysis of the practical results of the implementation of such a project in the existing serial building in Kyiv.
 The following research tasks were set: collection of general information about thermal energy distributors, their types and principles of operation; analysis of the current regulatory framework regarding the problem of individual accounting of thermal energy; analysis of the method of heat energy distribution adopted in Ukraine with identification of the main problems that arise during its application; analysis of practical results of thermal energy distribution in an apartment building in Kyiv.

Cost savings and CO2 emissions reduction potential in the German district heating system with demand response

Demand response (DR) has been an effective technique to maximize the proportion of renewable energies integrated into energy supply systems. This article investigated the benefits of DR on three building types (apartment building, office building and cultural center) and analyzed DR impacts on operation, production costs and CO2 emissions of three district heating (DH) production scenarios. The results indicate that the application of DR cuts 2.8%–4.9% off heating costs for building owners based on different energy production scenarios and building types. From the perspective of DH producers, the large-scale application of DR reduces the total DH demand by 3.6% to 3.9%. It results in higher financial benefits, less CO2 emissions and optimization of energy production in all the analyzed scenarios. The maximum total energy generation cost-saving rate is 12.6%, and the CO2 emissions reduce at most 32.3% because of a more renewable production mix. Moreover, DR control increases the full load operation hours of the heat pump, leading to higher efficiency, and decreases the operation hours of the boilers, leading to less pollution. It indicates that the application of DR effectively decreases fossil fuel usage and improves the energy efficiency of DH systems.

Temperature-adaptive radiative coating for all-season household thermal regulation.

The sky is a natural heat sink that has been extensively used for passive radiative cooling of households. A lot of focus has been on maximizing the radiative cooling power of roof coating in the hot daytime using static, cooling-optimized material properties. However, the resultant overcooling in cold night or winter times exacerbates the heating cost, especially in climates where heating dominates energy consumption. We approached thermal regulation from an all-season perspective by developing a mechanically flexible coating that adapts its thermal emittance to different ambient temperatures. The fabricated temperature-adaptive radiative coating (TARC) optimally absorbs the solar energy and automatically switches thermal emittance from 0.20 for ambient temperatures lower than 15°C to 0.90 for temperatures above 30°C, driven by a photonically amplified metal-insulator transition. Simulations show that this system outperforms existing roof coatings for energy saving in most climates, especially those with substantial seasonal variations.

Optimal design of heat exchanger network considering the fouling throughout the operating cycle

A model is established for minimizing the cost of heat exchanger network (HEN) throughout the operating cycle, with fouling, heat exchanger area margin, the location and opening of bypass considered. The Genetic Algorithm (GA) is applied to generate the economically potential structures; the neural network is used to predict the relationship of heat exchange area and cost. The flow velocity and bypass opening are optimized simultaneously by the Sequential Quadratic Programming (SQP) method. The optimization of HEN throughout the operating cycle is a mixed-integer nonlinear problem and is solved by the stage-wise solution procedure. The proposed method can efficiently optimize the design and operation of a HEN throughout the operating cycle. For the studied case, the total cost can be reduced by 62% after the optimization.

Techno-economic analysis of nitrogen-doped graphene/water nanofluid in various heat exchangers (A unified analysis)

Nitrogen-doped graphene (NDG)/water nanofluid is one of the emerging working fluids toward achieving high heating rates in heat transfer devices. In the present study, thermal performance improvement and techno-economic analysis of a double pipe, shell and tube, and plate heat exchangers are presented while incorporating NDG/water nanofluid as a working fluid. The variable properties of NDG nanofluid are incorporated and the influence of nanoparticle concentrations and mass flow rates on the device thermal performance and related costs are evaluated. The findings demonstrate that device heat transfer area and costs are adversely affected by using NDG/water nanofluid in all types of heat exchanging devices considered. An increase in heat transfer area is associated with the decrease of the specific heat capacity of the working fluid. The increase of heat transfer area can be as high as 58.5%, 45.1%, and 67.0% for double pipe, shell and tube, and plate heat exchangers, respectively. In addition, area increase becomes persistent with other types of nanoparticles used in the carrier fluid.

Heat transfer and cost analysis of circular heating source based tubular rods loaded with thermal oil-MWCNT nanofluid

Nanofluid is a suspension of nanoparticles (NPs) in conventional fluids. It has emerged as a smart material for transferring heat efficiently and has a great potential to be used as a coolant. In this work, nanofluid is designed by considering multi walled carbon nanotubes (MWCNT) suspended in heat transfer oil. The focus is on the heat transfer through natural convection for a specific geometry of circular heating source based tubular rods. In particular, this is representative of heating by micro-processors and other electronic components. Comsol Multi-Physics 5.5 software has been used for investigating the temperature and velocity profile for different concentrations of MWCNT NPs in this geometry. Significant enhancement in outlet temperature of the nanofluid even at low concentration of the NPs has been observed. This signifies an efficient heat extraction from the circular heat point sources (microprocessors) in the tube. On the basis of mathematical formulation, cost analysis of the proposed system has been performed and the cost per heat point source (Chps) has been estimated for fixed concentration of CNTs (0.5%) with interest rates of 4%,8%,and10%. For life spans of 30 and 50 years of the system, the corresponding Chps is found to be 12.34$,14.10$,15.55$and10.06$,12.98$,14.74$ respectively using CNTs. Moreover, the outlet of the proposed system can be coupled with other photovoltaic thermal (PVT) based systems as an application i.e., solar distillation and solar water heaters in order to improve their efficiency.

Multi-objective optimization of a cold-climate two-stage economized heat pump for residential heating applications

Energy consumption and environmental concerns are the two main drivers optimize heat pump systems. However, under extreme weather conditions especially in heating mode, conventional heat pumping systems face challenges when operating in cold-climates such as in Minneapolis, MN, USA. In the current work, a two-stage vapor injected heat pump system was optimized for residential applications at low ambient operating conditions using R-32, R-290, R-410A, R-454A and R–452B as working fluids. The system model was simulated using nondominated sorting genetic algorithm II (NSGA-II) method to obtain the Pareto-Frontier curves. The final solution for decision-making was selected based on a technique for order performance by similarity to ideal solution (TOPSIS) method. The system with R-32 and R-290 had a minimum unit cost of heat (UCH) of 0.19 $ kWh−1 and a maximum heating coefficient of performance (COP) of and 5.2, respectively. From the specific exergy costing (SPECO) analysis of the system, the results showed that the highest and lowest total investment cost were contributed with R-290 by 1.35 $ hr−1 and R-32 by 0.09 $ hr−1, respectively. Whereas, the maximum and minimum total cost rate of destruction were associated with R-290 by 1.73 $ hr−1 and R–452B by 1.33 $ hr−1, respectively.

Techno-economic analysis of waste-heat conversion

<h2>Summary</h2> With more than 50% of the primary energy consumed worldwide currently lost as waste heat, waste-heat conversion (WHC) should be considered a promising zero-carbon source of electricity. Despite significant research on WHC, the market penetration of such technologies remains limited, in large part because the R&D community has primarily focused on the development of new WHC heat engines with limited attention given to the techno-economic aspects. As different types of WHC heat engines vary significantly in their physical origins, there is a critical need to develop a system-level techno-economic model that is relatively independent of the detailed physics and design of the engine. In this perspective, we develop a techno-economic model for WHC technologies based on the well-known endoreversible thermodynamics formulations, which results in a fairly universal model. Our results indicate that regardless of the type or efficiency, WHC heat engines are not economically viable below 100°C, which has been the focus of significant research in the literature in recent years. Under highly optimistic assumptions, such as the cost of the WHC heat engines being the same as gas turbines (∼$0.25/W) and the capacity factor of the waste heat source being 0.9, for relative device Carnot efficiency <0.2, which is typical of various WHC heat engines, WHC is economical only for temperatures above 150°C and power output in the range of 100 kW to 1 MW. We conclude this perspective by providing a future outlook on the research needed in the field of WHC heat engines for it to be techno-economically viable. We also propose that along with the temperature and amount of waste heat available from various sources, the capacity factor of the waste-heat sources must be documented.

Harnessing of geothermal energy for a greenhouse in Ecuador employing a heat pump: design, construction, and feasibility assessment

Globally, the greenhouses' farming area comprises 500 000 ha, and they efficiently produce more than half of the vegetables consumed around the world. Nevertheless, high-yield crops tend to be incredibly energy-intensive. This study proposes designing and building a coupled geothermal heat pump for a 470 m2 greenhouse in the Andean zone conditions addressing a requirement of 15 °C at night and 30 °C during the day. Firstly, the study determined the energy potential of the solar and geothermal sources employing actual measurements and contrasting the results with theoretical models. Then, it developed an energy balance in the greenhouse to size the geothermal heat pump using the vapor compression cycle. Finally, the comprehensive system was built and evaluated through the Leveled Cost of Heat (LCOH). The operation requires a potential of 29.56 and 65.76 kW for heating and cooling; this is technically feasible when running the system with a heating flow driven by an optimized temperature ramp of 1.64 °C h−1. Also, the capacity factor (CF) shows that a lifespan between 12 to 14 years is required to reach acceptable LCOH when CF is as low as 0.45. Financially, it is necessary to foster customs exemptions to make it competitive versus more traditional sources such as electricity and LPG since the main components of the heat pump and the geothermal exchanger are not produced locally and represent nearly 70 % of the upfront costs.

Examining the Daylighting Performance of Office Buildings on the Example of the Rectorate Building in Izmir

The efficient use of energy resources has affected all areas of life, as well as architecture. There are many ways to increase energy efficiency in buildings. Supporting the efficient use of daylight in the design process, reducing the energy to be used for artificial illumination and reducing heating costs are among the applications that support energy efficiency. The issue of supporting daylighting by reducing artificial illumination draws attention, especially in office buildings, due to the high number of hours used during the day. Insufficient light and lack of visual comfort in offices used during the day increase the consumption of electrical energy. Within the scope of this study, a parametric study was conducted to optimize the daylighting performance of an office building. For this purpose, rectorate building of a university, which is used as an office building, was selected for the case study, and the daylight condition of this building was examined. For increasing the daylighting performance of the building some revisions were proposed. Results of this research are discussed with visuals and simulation values.