Air Heating System Research Articles

MINIMIZE ENERGY REQUIRMENETE FOR HEATING BROILER HOSUING

The main objective in brooding is to efficiently and economically provide a comfortable, healthy environment for growing birds. Bird's age is a governor factor to determine the heating load for broiler housing particularly during winter season. Forced air heating system should be put the broiler in thermal comfortable zone to obtain the higher production. Therefore, using perforated polyethylene duct to improve this heating system may cause better thermal conditions inside the broiler housing by reducing the temperature stratifications. So that the experiment was conducted out in private broiler house during winter season of 2011, under the climatic conditions of middle area of coastal Delta, Egypt (latitude and longitude angles are 30.67°N and 30.98°E, respectively). The obtained results showed that using perforated polyethylene duct increases the indoor air temperature throughout the bird's life, resulting in saved gas consumption by 32.6%, reduced litter moisture content from 41.5 to 32.8 %, reduced supplementary heatfrom 45.72 to 32.4 kWh and increased feed conversion efficiency from 60.4 to 62.2 at the end of birds life.

Harmony search algorithm and Lyapunov theory based hybrid adaptive fuzzy controller for temperature control of air heater system with transport-delay

The present paper proposes systematic designs of stable adaptive fuzzy logic controllers (AFLCs), employing hybridizations of Lyapunov strategy based approach (LSBA) and a contemporary stochastic optimization technique, for controlling the temperature of a thermal process in an air-heater system with transport-delay and in the presence of disturbances. Harmony search (HS) algorithm has been considered here as a candidate stochastic optimization technique utilized in conjunction with the Lyapunov theory to develop the hybrid models in this work. The objective of this work is to design stable adaptive fuzzy controllers which can provide high degree of automation, guarantee asymptotic stability and also achieve satisfactory transient performance by simultaneous adaptations of both the fuzzy controller structure and its free parameters. The results obtained from real-life experiments aptly demonstrate the usefulness of the proposed approach.

Greenhouse heating by solar air heaters on the roof

A solar air heater (SAH) system was investigated experimentally for heating an innovative greenhouse in Baghdad, Iraq (33.3 °N, 44.4 °E). The innovative greenhouse combined a traditional greenhouse and a bank of solar air heaters on the roof as one structure. This arrangement did not affect the required solar radiation inside the greenhouse for winter heating when compared with a conventional greenhouse. An energy balance method was used to calculate the heating load. This differs from the previous standard method which does not include soil heat storage. The soil surface heat gain was considered in the present work and was found to contribute 13–19% of the heating load required. Six solar air heaters with a single glass cover and a ‘V’ corrugated absorber plate connected in parallel were mounted on the greenhouse roof. Tests were carried out in the winter season of 2012. The mass flux of air through the collectors was varied from 0.006 to 0.012 kg/s.m2. An air mass flux of 0.012 kg/s m2 was found to provide about 84% of the daily heat demand to keep the greenhouse inside air temperature at 18 °C. The summation of a would be stored energy from the SAHs and a stored free solar heat inside the greenhouse can cover all the daily heating demand with an excess of approximately 46%.

Experimental based energy performance analysis and life cycle assessment for solar absorption cooling system at University of Californian, Merced

Traditional air conditioning and heating systems in buildings are fossil fuel based energy systems, which take the main responsible for the carbon emissions. In contrast, using solar energy for air conditioning becomes one of the promising approaches to reduce energy consumptions and negative environmental impacts from buildings. University of California, Merced built a test facility to investigate the technology: solar cooling. The solar system has 54m2 external compound parabolic concentrator (XCPC) solar collectors to drive a 23kW double-effect absorption chiller. This paper first provides the detailed energy performance analysis of the experiments conducted in August, 2012. The data collected from the experiments shows that the system could provide adequate cooling for a test facility between 11AM to 5PM in both sunny and cloudy days. The daily average collector efficiency is at the range of 36% to 39%. The average coefficient of performance (COP) of the LiBr absorption chiller is between 0.91 and 1.02 with an average of 1.0, and the daily solar COP is approximately at 0.374.In addition to the experimental investigation, a detailed life cycle economic and environmental assessment was also performed by comparing the solar systems to the conventional systems in two types of office buildings at three locations at California. Two different solar cooling system configurations were considered: (i) configuration 1 sizes the area of solar collectors and absorption chiller to meet the peak cooling demand, and uses natural gas as the only backup energy source; (ii) configuration 2 sizes the area of solar collectors and absorption chiller to meet half of the peak cooling demand, and uses natural gas as the backup energy source for the absorption chiller, while incorporates an electrical vapor compression chiller to meet the rest half of peak cooling demand. The annual performance predicts that the systems can achieve the annual solar fraction around 55–68%. And the configuration 2 achieves better life cycle economic and environmental performance than the configuration 1. Specifically, the configuration 2 can achieve lower present worth cost during the entire life span than the conventional systems. And both configuration 1 and 2 can reduce the life time carbon footprint by 35–70%.

Design of Virtual Corolla 1.6AT Automatic Air Conditioning Experiment Bench

This paper introduces a virtual experiment bench for automotive air conditioning. In the experiment bench based on the experiment bench for Corolla 1.6AT automatic air conditioning, the refrigeration, heating, gas distribution and other mechanical systems are removed and the electrical control system is reserved using the virtual and simulation theory. The experiment bench has the features, such as simple structure, low production and operation cost, safety and environmental protection; its main sensor signals are simulated through a variable resistance, the working processes of some actuators are shown by light bulbs, so that it is easy to operate the experiment bench, and the working process is visual and direct. The experiment bench can be self-developed, designed and produced by students under the guidance of teachers, thus to promote the comprehensive ability of students to use knowledge and innovate.

Resolving National Energy Crisis through Energy Efficient Appliances: Use of Ground Water Heat Pump for Air Conditioning Systems

Energy crisis are deepening with every year passing by in a country like Pakistan. One of the major contributors of energy consumption in the domestic as well as in some commercial sector is the environment air conditioning (during summers) and heating systems (during winters). One possible solution to this national energy crisis is available in the form of tapping the available renewable natural resources of energy, specifically the Ground Water Heat Pumps (GWHP). Despite its wider applications in the advanced countries, the confidence in this technology is much feeble in less advanced countries, like Pakistan, mainly due to lack of awareness about the technology among the public and lack of subsoil temperature data for the scientific / engineering community. Thus, the aim of this study is to collect subsoil water temperature data of at least one particular location for over a year, and demonstrate the usefulness of sub soil ground water in improving the performance of conventional air-conditioning system both in cooling as well as in heating modes. This study shows significant improvement in the Coefficient of Performance (COP) of the Air Conditioner both in Cooling as well as in heating modes and thus reducing the expensive electricity consumption.

Approach of a solar building integrated with multiple novel solar technologies

A novel solar building is constructed in Hefei, China. The solar energy can supply the building with solar power, solar space heating, solar-cooling and solar-hot water by corresponding novel solar technologies and components. Preliminary simulation by TRNSYS showed that the solar building could reduce >30% of the energy consumption compared with the same scale of the office building in Hefei during the heating season. In an experiment performed on 20 February 2013, the max temperatures of both the north room and south room reached 21°C and the average temperatures were 17°C, only using the solar air heating system.

Temperature gradient sensor from pulsed power supply duty cycle in ultra‐low‐power energy harvesting system

Directly interfacing sensors that link sensors to micro-controllers without a signal conditioning circuit or an analogue-to-digital converter on the one side and energy harvesting systems on the other side are two key enabling technologies to create self-powered autonomous low-cost and low-maintenance sensor networks. In this reported work, both technologies are concurrently combined in such a way that the duty cycle of the pulsed power supply provided by the harvesting system itself yields in turn a temperature gradient sensor functionality. Originally conceived to power a low-power satellite beacon in a CubeSat project, it has found application, among other applications, in automatic air conditioning and heating systems aiming smart buildings.

In brief

PAGE 786 Research from Pakistan and the UK presents a novel dual-port diversity/MIMO antenna for UWB applications. The system is compact and suitable for non-planar applications as well as being reconfigurable. The MIMO elements can be placed in stacked/back-to-back as well as in orthogonal/around-corner arrangements. Compact and reconfigurable systems (including UWB) are important for Wide Personal Area Networks. PAGE 826 A system that implements a temperature gradient sensor and a beacon signal transmitter has been proposed in work from Spain. The system is fully autonomous and self-powered by energy harvesting from a very low temperature gradient. It was originally conceived to power a low-power satellite beacon and has found applications in automatic air conditioning and heating systems. Novel dual-port diversity/MIMO antenna has potential ultrawide band applications PAGE 833 A novel computational technique to study the terminal influence inside the three-dimensional nano-scale MOSFET using Technology CAD simulations is shown in work from the United States. Within the MOSFET, the derivative of the electrostatic potential can be taken with respect to voltages at each terminal; when these derivatives are summed together, they always sum to unity. These functions can be used to quantify the relative influence or control of terminals anywhere inside the MOSFET, including the channel. Temperature gradient sensor and beacon signal transmitter used in automated air-conditioning and heating systems PAGE 817 Researchers in the United States have demonstrated the first contactless radio frequency (RF) probes for on-wafer characterisation of microwave integrated circuits (MICs) at temperatures as high as 200°C. The high-temperature contactless probing techniques overcome the limitations of conventional ground-signal-ground coplanar waveguide probes, which rely on good physical contact. They provide a fast, reliable and inexpensive method to quickly screen MICs for high temperature RF telemetry. Novel computational technique is presented to study the terminal influence inside the three-dimensional nano-scale MOSFET PAGE 799 Researchers in Japan present a PLZT capacitor fabrication process with better hydrogen degradation resistance and fatigue endurance by adding a thin aluminium-doped zinc oxide (AZO) buffer layer. This could be applied to ferroelectric random access memory, MEMS and piezoelectric fields. The hydrogen degradation resistance of the PLZT capacitors was improved by over 80% of an initial polarisation value. Contactless radio frequency probes provide a fast, reliable and inexpensive method to quickly screen MICs for high temperature RF telemetry Issue 1 of the IET's latest Letters journal is now available at www.theiet.org/htl with trial access to all content throughout 2014

Heat Transfer Enhancement in a Solar Air Heater Channel with Discrete V-Baffles

This article presents the study of heat transfer enhancement in a uniform heat-fluxed channel fitted with discrete V-shaped baffles. The experiments are carried out by varying airflow rate for Reynolds number ranging from 4100 to 22,000. The V-baffles with relative height ratio, e/H = 0.15 and the attack angle, α = 45o, are mounted repeatedly on the upper plate only, similar to an absorber plate of solar air heater systems. The effects of four baffle-pitch to channel-height ratios (PR= 0.5, 1.0, 1.5 and 2.0) on heat transfer in terms of Nusselt number and pressure loss in the form of friction factor are experimentally investigated. The experimental results show that the use of the discrete V-baffles leads to a considerable increase in Nusselt number and friction factor in comparison to the smooth channel alone. The V-baffled channel with PR=0.5 provides the highest heat transfer, friction factor and thermal enhancement factor.

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer.

A conveyor-belt dryer was developed using a combined infrared and hot air heating system that can be used in the drying of fruits and vegetables. The drying system having two chambers was fitted with infrared radiation heaters and through-flow hot air was provided from a convective heating system. The system was designed to operate under either infrared radiation and cold air (IR-CA) settings of 2000W/m(2) with forced ambient air at 30°C and air flow of 0.6m/s or combined infrared and hot air convection (IR-HA) dryer setting with infrared intensity set at 2000W/m(2) and hot at 60°C being blown through the dryer at a velocity of 0.6m/s or hot air convection (HA) at an air temperature of 60°C and air flow velocity 0.6m/s but without infrared heating. Apple slices dried under the different dryer settings were evaluated for quality and energy requirements. It was found that drying of apple (Golden Delicious) slices took place in the falling rate drying period and no constant rate period of drying was observed under any of the test conditions. The IR-HA setting was 57.5 and 39.1% faster than IR-CA and HA setting, respectively. Specific energy consumption was lower and thermal efficiency was higher for the IR-HA setting when compared to both IR-CA and HA settings. The rehydration ratio, shrinkage and colour properties of apples dried under IR-HA conditions were better than for either IR-CA or HA.

Experiment and prediction of hybrid solar air heating system applied on a solar demonstration building

Abstract As solar space heating is one of the most efficient ways to reduce fossil energy consumption, a hybrid solar air heating system for building space heating is proposed in this paper. The system includes passive and active dual function solar collectors. It was tested on a solar demonstration building, which was located on USTC (University of Science and Technology of China, Hefei China) campus. Different operation strategies of the hybrid solar air heating system were tested experimentally in order to evaluate heating effect of the system. The results showed that the strategy of passive solar heating for southern room space heating and active solar heating for northern room was a better operation strategy, by which the average indoor temperature of both southern and northern rooms reached 17.0 °C during the experiment. Based on the experimental results and software of TRNSYS simulation, the solar fractions of the system during the heating season in Hefei and Nyingchi were predicted with values of 39.5% and 69.0%, respectively. Above all, it presented an efficient design philosophy for building to utilize solar energy for space heating.

EVALUATION OF AIR HEATING SYSTEMS EFFECTIVENESS IN GREENHOUSES

The results of experimental studies of gas-air heat exchanger of solid fuel stove are viewed. Work modes of air heating system in the greenhouse are measured. Work modes of stove and gas-air heat exchanger are analyzed. Dependence between air temperature from heat exchanger and heating mode is established.

Lessons learned from fire in air supply ducts

In 2012, loss of air flow caused activation of interlocks to shut off steam and electrical heat inputs to an air heating system that was part of a drying/milling operation. Shortly thereafter, upstream filters and air ducts ignited causing more than US$500K in damage and business interruption. Investigations concluded that the interlocks functioned as designed on loss‐of‐airflow but were not sufficient to prevent overheating the inlet air filters (including HEPA filters) by the residual heat in the air heaters. The two main lessons learned from this fire incident apply to a broad range of operations in the chemical process industries (CPI): Mundane unit operations such as air filters that have combustible components must be evaluated as thoroughly as the rest of the chemical process. Designers and PHA leaders must recognize the potential of thermal inertia of heaters (and coolers) to heat (or cool) a stagnant volume of fluid when flow is interrupted. Gas streams are particularly susceptible due to the low heat capacity relative to the heat capacity of a metallic heat exchanger. Interlocking the supplies (to steam and electrical heaters in this incident) is often necessary but may not be sufficient. Other lessons “relearned” include the importance of learning from a previous near miss, the importance of limiting escalation aspects of this fire, and the importance of preventative maintenance. © 2014 American Institute of Chemical Engineers Process Saf Prog, 2014

Development of a cassette-panel transpired solar collector

Transpired solar collectors (TSCs) are an elegantly simple, façade-integrated solar air-heating technology that is widely used to pre-heat the ventilation air supply of buildings. TSCs have historically been manufactured from long profiled pre-finished steel cladding sheets and used on industrial buildings, with which they are aesthetically compatible. Buildings such as offices and multi-storey residential buildings, however, often use flat building façade elements. In order to provide architects with the choice between a profiled or flat TSC absorber, which may be more suitable aesthetically in some circumstances, a novel, flat, cassette-panel TSC (CP-TSC) solar air-heating system has been developed and trialled in situ. Two prototype CP-TSC systems were installed onto an unoccupied 1960s multi-storey residential building at Oxford Brookes University and operated for 95 days during the winter of 2010/2011. The results show that under typical operating conditions, the CP-TSCs heated the ventilation air stream by 10–15°C on clear-skied, winter days, and that this air temperature rise can be predicted by a relatively simple energy balance model.

Heat transfer and fluid flow analysis of artificially roughened ducts having rib and groove roughness

Artificially roughness is one of the well known methods of enhancing heat transfer from the heat transfer surface in the form of repeated ribs, grooves or combination of ribs and groove (compound turbulators). The artificial roughness produced on the heat transferring surface is used in cooling of gas turbine blades, nuclear reactor, solar air heating systems etc. Solar air heaters have wide applications in low to moderate temperature range, namely, drying of foods, agricultural crops, seasoning of wood and space heating etc. Solar air heaters have low value of convective heat transfer coefficient between the working fluid (air) and the heat transferring surface, due to the formation of thin laminar viscous sub-layer on its surface. The heat transfer from the surface can be increased by breaking this laminar viscous sub layer. Hence, in the present work compound turbulators in the form of integral wedge shaped ribs with grooves are used on the heat transfer surface, to study its effect on the heat transfer coefficient (Nusselt number) and friction factor in the range of Reynolds number 3,000–18,000. The roughness produced on the absorber plate forms the wetted side of upper broad wall of the rectangular duct of solar air heater. The relative groove position (g/p) was varied from 0.4 to 0.8 and the wedge angle (Φ) was varied from 10° to 25°, relative roughness pitch (p/e) and relative roughness height (e/D) was maintained as 8.0 and 0.033 respectively. The aspect ratio of the rectangular duct was maintained as 8. The Nusselt number and friction factor of the artificially roughened ducts were determined experimentally and the corresponding values were compared with that of smooth surface duct. It is observed that wedge-groove roughened surface shows more enhancement in heat transfer compared to only rib roughened surface arrangement. The investigation revealed that Nusselt number increases 1.5–3 times, while the friction factor increases two to three folds that of the smooth surface duct in the range of operating parameters. It is also observed that in rib–groove roughness arrangement with relative groove position of 0.65 shows the maximum enhancement in the heat transfer compared to the other rib-groove roughness arrangements. Statistical correlations for the Nusselt number and friction factor have been developed by the regression method in terms of the operating and roughness parameters. A program was also developed in MATLAB for the calculation of thermal efficiency and thermal effectiveness. It was observed that the thermal efficiency is more for wedge angle of 15° and relative groove position of 0.65 and its value ranges from 42 to 73 %. The uncertainties in the measurements due to various instruments for the Reynolds number, Nusselt number, and friction factor have been estimated as ±3.8, ±4.54 and ±7.6 % respectively in the range of investigation made.

Simulation on Building Energy Consumption for a Residential Building

A two floor residential building in Tianjin as the research object was studied in this paper. The software eQUEST was carried out to simulate residential buildings energy consumption, and to explore the annual total energy consumption of the residential building, which was influenced by air conditioning heating modes and the building orientations. The air conditioning and heating system modes used to simulate including the heat pump air conditioning, air conditioner & heat sink and radiant heating & heat sink. The simulated building orientations include east, west, south and north. The transformation of the sunshade direction could be obtained by changing the building orientation. The indoor design temperature in summer was set at 26°C, while winter design temperature was set at 18°C. As the result of the energy consumption simulation study showed that, the annual total energy consumption achieved the minimum when heat pump type air conditioning heating system was adopted. When the effected factors such as air conditioning heating system, indoor heat source condition, window size and some other factors which influenced energy consumption were constant, the simulation results might be found that the building orientation had a small influence on the building energy consumption.

Experimental investigation of a dual purpose solar heating system

In this study, a dual purpose water and air heating system is experimentally investigated. The system consists of a dual purpose flat solar collector and a vertical water storage tank. Water and air have natural and forced convection in the collector, respectively. The reason why dual purpose systems are used is to achieve greater efficiency and lower heat dissipation. Furthermore, high temperature and high performance can be obtained using this solar collector. These systems can be used to heat water and air simultaneously or separately. The hot water can be utilized for domestic applications or as a PCM material for heating air through the night. Besides, the hot air can be used in air conditioning systems, industrial processes and dryers. Therefore, using these collectors brings high energy savings. Absorber plate temperature variation, storage tank average temperature, system efficiency and air velocity effects are presented. Moreover, hourly efficiency is compared for single purpose and dual purpose systems. The results indicate that the efficiency of the dual purpose system is 3 to 5% higher than a single purpose system.

Potential application of glazed transpired collectors to space heating in cold climates

Although unglazed transpired collectors (UTC) succeed in industrial ventilation applications, solar fraction is very low when they are used in space heating in cold climates due to the lower exit air temperature. Considering the potential for glazed transpired collectors (GTC) using recirculated air for space heating applications in cold climates, a mathematical model is developed for predicting the thermal performance of GTC. Simulation results show that although glazing results in optical loss, it could decrease convective heat loss resulted from high crosswind velocities effectively. For a solar radiation of 400W/m2, an ambient temperature of −10°C, and a suction velocity of 0.01m/s, the exit air temperature of GTC is higher than that of UTC for crosswind velocities exceeding 3.0m/s. By comparison with a conventional flat-plate solar air collector operating under the same conditions, the thermal performance of GTC shows a significant improvement. For a five-storey hotel building located in the severe cold climate zone of China, case study shows that the annual solar fraction of the GTC-based solar air heating system is about 20%, which is two times higher than that of the flat-plate collector-based system and nearly nine times higher than that of the UTC-based system respectively. Hence, an enormous amount of energy will be saved with the application of GTC to space heating in cold climates.

Weatherization, IEQ and Building Performance: Study Methodology and Pre-weatherization Baseline

The accelerated rate of implementing energy-efficiency measures in residential homes is outpacing our knowledge of the potential impacts on the indoor environment quality (IEQ). To address both the occupant exposure and potential contributing factors, real-time data (temperature, %RH, CO2, CO, particulate matter, total volatile organic compounds, formaldehyde, radon) were collected in pre-weatherization homes during the 2012-2013 heating season. Average NO2 values were also collected using passive samplers. Participants were recruited from ongoing Weatherization Assistance Programs through partnerships with community action agencies located in North Carolina’s diverse mountain and coastal zones. Other data being collected for analyzing pre/post-weatherization differences, include participant activities, exhaust fan and blower door measurements, building features, and occupant characteristics (smoking, pets). Results for data from ten pre-weatherization homes at each location indicate the following: CO, formaldehyde, NO2, and radon below acceptable levels in all test homes, except one with high NO2; six homes, somewhat elevated TVOCs (five in the mountains); eleven homes, elevated PM2.5 (eight at the coast); three homes carbon dioxide above 1000ppm. Comparison of homes with and without forced air heating systems show significantly higher counts of particulate matter in homes with forced air systems: an order of magnitude more 0.3 mm and 0.5 mm particles; similar amounts of 1.0 mm, 2.5 mm particles; and 50-100% more 5.0 mm and 10 mm particles. Average values for outdoor samples at both locations indicate that all parameters are less than indoor values, except values for particle sizes 1.0 mm, 2.5 mm, 5 mm, and 10 mm at the coastal location. Additional analysis comparing data from two NO2 passive samplers and two wind speed sensors at WAMY study homes, showed good agreement (< 2ppb) for the NO2 samplers, and an average difference of 45% for the wind speed sensors.