Heater Heat Research Articles

Inverse problem of flame surface properties of wood using a repulsive particle swarm optimization algorithm

The convective heat transfer coefficient and surface emissivity before and after flame occurrence on a wood specimen surface and the flame heat flux were estimated using the repulsive particle swarm optimization algorithm and cone heater test results. The cone heater specified in the ISO 5660 standards was used, and six cone heater heat fluxes were tested. Preservative-treated Douglas fir 21 mm in thickness was used as the wood specimen in the tests. This study confirmed that the surface temperature of the specimen, which was calculated using the convective heat transfer coefficient, surface emissivity and flame heat flux on the wood specimen by a repulsive particle swarm optimization algorithm, was consistent with the measured temperature. Considering the measurement errors in the surface temperature of the specimen, the applicability of the optimization method considered in this study was evaluated.

Динамическая модель отопительных приборов и систем

In order to develop previously performed work we consider the problem of constructing a dynamic mathematical model of heating devices and systems. The heating system at the same time seems to be equivalent heater. The output value of the model in this case is the power (heat capacity). Decision is executed by the "gray box", that is the structure of the model is determined by analyzing the physics of the processes occurring in heating devices and systems, and the numerical values of its parameters are found from the experimental data by parametric identification. The resulting differential equation is linear with respect to the unknown quantity-power heater(heating), input the same size-water inlet temperature of the heating system and the temperature of the indoor air are included in this equation in a linear fashion, and the flow is in non-linear manner. It is shown that a constant flow of coolant model can be represented by the transfer functions in the iso-mapping Laplace transfer function of the channel "coolant temperature at the inlet to the heater(heating system) – thermal capacity of the heater(heating)" is a inertia component of the first order, and the channel "indoor air temperature-heat capacity of the heater(heating)" - inertia-forcing component with a negative coefficient of transmission. The qualitative features of the model parameters, in particular, their dependence on the coolant flow are analyzed. Algorithmic block diagram of the control object, which includes the heating system and the thermal regime of the building itself is provided. The results of the parametric model identification from experimental data is described. The model can be used in the development of intelligent control systems heating buildings.

Case Analysis of the Solar Heating System Assisted by Condensing Wall-Mounted Gas Heater

Taking household heating for an example, this paper has introduced the composition and characteristics of combined heating system with condensing wall-mounted boiler and solar water heater; and through the simple contrastive analysis of the economy and environmental protection with the solar heating system assisted by electric heating and wall-mounted gas heater, it is believed that the heating system combined with condensing gas heater and solar heating is the better choice of household heating considering its energy saving, economy and environmental protection.

The effect of water temperature lift on the performance of cascade heat pump system

The mass flow rate of secondary fluid in a water heater heat pump determines not only the discharge water temperature but also the heat pump performances. As water flow rate decreases, water discharge temperature increases; however, the COP (coefficient of performance) deteriorates due to the increase of high side pressure. In this study, cascade cycle which is used for a water heater heat pump was studied to verify the effect of the water temperature lift in terms of pressure and performance change. Also, the optimal intermediate temperature of cascade cycle with respect to temperature lift was studied and this temperature was adopted for a heat pump transient operation. The heat pump was operated to meet the constant heating capacity and target intermediate temperature by PID control of compressor speed. The transient results showed that water temperature lift determines not only the vertical temperature profile of water reservoir but also the transient performance.

The Design of Solar Heating System for Oil Field Duty Room

Based on the natural environment of Gansu YuMen oilfield in china, aiming at the winter heating requirements for oil field duty room, using the solar heating system that make solar energy storage and auxiliary electric heating, selection of flat plate collector, tacking double working medium for heat exchange indirectly, use the antifreeze liquid as the hot working medium, use the water as the energy storage and heating medium. According to the room temperature and medium temperature, intelligent control system adjust and control the double medium circulation loop, automatic regulating the intermittent work time for auxiliary electric heating system, the problem of antifreeze and sand prevention be solved effectively in the extreme temperatures. Compared to the electric heater heating, it can realize energy saving and environmental protection, the energy saving effect more than 46%, having remarkable economic and social benefits.

A Data Reconciliation Based Approach to Accuracy Enhancement of Operational Data in Power Plants

Accuracy of operational data of a power plant is essential for power plant performance monitoring and fault diagnosis. However, due to inevitable occurrence of systematic and measurement errors in the course of obtaining operational data, these errors can only be reduced to a certain level but never be eliminated. In this work, we propose a data reconciliation based approach to reduce the errors of operational data thus enhance the accuracy of the data. The reconciled data can then be used in performance monitoring and fault diagnosis systems to improve their performances. The proposed method is based on more efficient use of redundant data and a first-principle mathematical model of a power plant. Then an optimization process is performed where the weighted least square form of aggregated differences between measured data and their estimated values are minimized. To illustrate the capability of the proposed method, we provide a case study of data reconciliation for feedwater heater heat balance analysis in a 660 MW coal- fired power plant in China. Results show that uncertainty of four key parameters, namely feed water mass flow rate, condensate mass flow rate, deaerator pressure and outlet temperature, can be reduced by 24 %, 30 %, 5 % and 65 %, whilst the uncertainty of other parameters are also reduced to various extent. Moreover, the results also indicate that the proposed approach is effective over a wide range of measured data quality, where quality of some data could be much worse than others and the estimated measurement uncertainties of operational data may not be accurate.

Effect of the Fast Pyrolysis Temperature on the Primary and Secondary Products of Lignin

This paper presents results on the primary pyrolysis products of organosolv lignin at temperatures between 360 and 700 °C. To study the primary products, a vacuum screen heater (heating rate of 8000 °C/s, deep vacuum of 0.7 mbar, and very fast cooling at the wall temperature of −100 °C) was used. The effect of the temperature on the primary and secondary lignin products was studied with a fluidized-bed pyrolysis reactor (Treactor between 330 and 580 °C) with pine wood. The results obtained with the screen heater show that the primary products of lignin were oligomers. Between 450 and 700 °C, the yield of these oligomers was very high, between 80 and 90%. After formation, the oligomers left the particle by evaporation or thermal ejection. Monophenols and other light compounds were formed by secondary reactions inside the particle or in the vapor phase. In the fluidized-bed reactor, significant quantities of lignin oligomers were formed along with monophenols, water, and other light compounds. The changes o...

The use of a heater and borehole heat exchangers for the regeneration of heat resources in the rock mass on the example of the Geoenergetics Laboratory, AGH UST

The use of a heater and borehole heat exchangers for the regeneration of heat resources in the rock mass on the example of the Geoenergetics Laboratory, AGH UST

Note: Development of fast heating inert gas annealing apparatus operated at atmospheric pressure

Here, we report the development of a simple, small, fast heating, and portable, homemade, inert gas (Ar) atmospheric annealing setup. Instead of using a conventional heating element, a commercial soldering rod having an encapsulated fast heating heater is used here. The sample holder is made of a block of stainless steel. It takes 200 s to reach 700 °C, and 10 min to cool down. The probability of oxidation or surface contamination has been examined by means of x ray photoelectron spectroscopy of virgin Cu sample after annealing at 600 °C. In addition, we compare the annealing of a hydrogenated carbon nitride film (HCN(x)) in both a conventional vacuum and our newly developed ambient Ar atmosphere setup.

Coal-fired small-capacity cogeneration station with a two-zone gas generator with a fluidized bed

The operation of coal gas generator with a fluidized bed is considered, the air gasification products of which are used in the gas-piston internal-combustion engines (ICE) with the electric generator and in the network heaters (heat utilizers) for the heat supply.

Exploring variance in residential electricity consumption: Household features and building properties

Improved means of controlling electricity consumption plays an important part in boosting energy efficiency in the Swedish power market. Developing policy instruments to that end requires more in-depth statistics on electricity use in the residential sector, among other things. The aim of the study has accordingly been to assess the extent of variance in annual electricity consumption in single-family homes as well as to estimate the impact of household features and building properties in this respect using independent samples t-tests and one-way as well as univariate independent samples analyses of variance. Statistically significant variances associated with geographic area, heating system, number of family members, family composition, year of construction, electric water heater and electric underfloor heating have been established. The overall result of the analyses is nevertheless that variance in residential electricity consumption cannot be fully explained by independent variables related to household and building characteristics alone. As for the methodological approach, the results further suggest that methods for statistical analysis of variance are of considerable value in indentifying key indicators for policy update and development.

Pressure Testing Feedwater Heaters and Power Plant Auxiliary Heat Exchangers

This paper discusses factory and field pressure testing of tubular heat transfer equipment such as closed feedwater heaters, steam surface condensers, and power plant auxiliary heat exchangers built in accordance with Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code (the ASME Code) and repaired or altered in accordance with the National Board Inspection Code (NBIC) (The ASME issues the ASME Boiler and Pressure Vessel Code at three-year intervals and issues Addenda annually; The National Board Inspection Code (NBIC), 2007 edition (three volumes), ANSI/NBBPVI NB23-2007, The National Board of Boiler and Pressure Vessel Inspectors, Cleveland, OH). It discusses the ASME Code’s and the NBIC’s requirements for hydrostatically testing unfired pressure vessels, which include tubular heat transfer equipment. It shows by analysis that using pressure gauge indications of pressure loss to determine if there is a leak from the tube side to the shell side when the back face of the tubesheet is not visible does not reveal very small leaks or weeping. For the purposes of this paper, we define weeping, Vleak, as a leak of 20 drops/h or approximately 1 cm3/h(0.061 in.3/h). During typical half-hour hydrostatic test pressure-holding periods, such weeping would amount to 10 drops of water on the tubesheet face or 0.5 cm3(0.0305 in.3). Weeping through tube-to-tubesheet joints of high pressure feedwater heaters can lead to wire drawing (wormholing), which can materially reduce the heater life. Leaks from the channel to the shell side of steam surface condensers and auxiliary condensers can introduce brackish water into the condensate. Depending upon the fluid flowing in the tubes, contaminants can enter the shell side of other auxiliary equipment when the channel pressure is higher than that of the shell. This paper concludes that users must advise designers and manufacturers of the hazards of small leaks through the tube-to-tubesheet joints. It recommends that these three entities must agree on suitable leak tests.

Improved area—energy targeting for fired heater integrated heat exchanger networks

Effective integration of various subsystems into the overall process, results in an energy efficient and economic plant design. In this paper, issues related to the area-energy targeting for fired heater integrated heat exchanger networks are studied. Performance of a fired heater is affected by the variables such as fuel fired and air-preheat temperature. These variables along with the minimum approach temperature difference for the heat recovery of the background process, affect the performance of the overall system. A methodology is proposed for the area-energy targeting for fired heater integrated processes. In the proposed methodology, the fired heater heat duty split between the radiation and the convection section is determined using the one gas zone furnace model.

Simulation aided hot zone design for faster growth of CZ silicon mono crystals

Computer simulation was used for optimizing a hot zone for Czochralski (CZ) silicon crystal growth. The heater structure and heat shield material were investigated. With this optimized hot zone, the temperature gradient near the crystal/melt interface increased and the CZ crystal could be grown at a faster rate. It is a great contribution for saving power consumption.

A study on control of heater power and heating time for thermoforming

Obtaining a uniform thickness of the final product using thermoforming is difficult, and the thickness distribution depends strongly on the distribution of the sheet temperature. In this paper, the time-dependent temperature distribution of the total sheets in the storing stage was studied because the temperature after the storing stage is the initial temperature of the heating process. An analytic solution for simulating the storing stage was derived. Using the solved analytic solution, the time-dependent temperature distribution of the total sheets was found out under the condition of assuming that the temperature-dependent specific heat of the ABS sheets was a certain constant value. Finally, the control method for a successful thermoforming using the heater power or heating time was researched in order to improve the quality of the final products. The results show that the satisfied temperature distribution can be obtained by adjusting the heater power or heating time. The method for analysis in this study will be used to improve the quality of the final products.

A Study on Manufacturing Efficiency and Quality of Thermoforming

Thermoforming is one of the most versatile and economical processes available for shaping polymer products. The heating time and heater power must be optimized for obtaining good products efficiently. In this study, the method for calculating the required heat flux was researched at first. In the following step, the analytic solution was studied for getting optimal heating time and heater power. Finally, the relationship between heater power and heating time was discussed. The developed method in this study will be widely used to shorten the cycle time under the condition of satisfying requirements of thermoforming.

Energy and exergy analysis of multi-functional solar-assisted heat pump system

This paper reports the exergetic modeling and performance evaluation of a novel multi-functional solar-assisted heat pump (SAHP) system based on an experimental study. Comparisons between the multi-functional SAHP system and conventional hot water heating systems, i.e. electric water heater, gas-fired water heater and air source heat pump, are made with respect to energy and exergy efficiencies. The results show that the multi-functional SAHP system has the highest energy performance, average 2.98. In addition, the multi-functional SAHP system offers the highest exergy efficiency among the four kinds of hot water heating systems. Copyright The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org, Oxford University Press.

Evaluating energy, health and carbon co-benefits from improved domestic space heating: A randomised community trial

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A – assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B – assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1.

Upgrading home heating systems improved subjective symptoms in children with asthma

P Howden-Chapman Prof P Howden-Chapman, University of Otago, Wellington, New Zealand; philippa.howden-chapman@otago.ac.nz Does upgrading home heating systems improve the health of children with asthma? ### Design: randomised controlled trial. ClinicalTrials.gov...

422 CO_2 as Refrigerant for Water Heater Heat Pump : Comparing Performance during Nighttime and Daytime in Winter Time(International Session)

422 CO_2 as Refrigerant for Water Heater Heat Pump : Comparing Performance during Nighttime and Daytime in Winter Time(International Session)