Showing papers on "Heating system published in 1997"

Hybrid catalyst heating system with water removal for enhanced emissions control

Abstract: The present invention provides a method and apparatus for heating a catalytic converter at least to a light off temperature. In accordance with the invention, the catalytic converter may be heated using a novel monolith construction, electrical heating, catalytic combination of a fuel and oxygen or combinations of these methods. Heating or thermally conditioning a catalyst in accordance with the invention rapidly brings the catalyst up to the light off temperature for the efficient conversion of pollutant gases, such as unacceptable emissions emanating from an internal combustion engine, into water, carbon dioxide and other acceptable emissions. In particular, the invention provides efficient heating of the catalytic converter despite the potential presence of water on the catalyst during startup.

Electronic boiler control

Abstract: A hydronic heating system including a single self-contained hydronic control unit. The hydronic control unit allows for zoned heating operation in which a series of individual room thermostats and zone valves control the flow of heated water into each of the heating zones. The hydronic control unit operates an oil or gas fired boiler to maintain boiler water temperature at a selected value. The hydronic control unit includes a priority terminal which can be connected to a priority heating zone, such as an indirect fired water heater. Upon receiving a demand for heat from the priority heating zone, the hydronic control unit diverts the flow of heated water from the boiler to the priority zone exclusively. The hydronic control unit further includes a terminal for connection of an outdoor air sensor. In cooperation with the outdoor air sensor, the hydronic control unit can operate in a boiler reset operating mode such that the boiler temperature is related to the outside air temperature. The hydronic control unit includes a terminal for connection of a hot water sensor, which is also connected to a safety terminal. The hot water sensor indicates the temperature of water in the boiler, and provides a safety switch should the water in the boiler exceed an upper limit. The hydronic control unit further includes connection for a low water cut-off probe that interrupts the power to the hydronic control unit should the quantity of water in the hydronic heating system fall below a minimum value. The hydronic control unit incorporates the above-identified features in a single control housing, such that only one power connection is needed for the above-identified features.

Apparatus for drying and heating using a pulse combustor

Abstract: The present invention is directed to drying and heating processes and to an apparatus incorporating a pulse combustion device that can be used in a drying system or in a heating system. In general, the apparatus includes a pulse combustion device for the combustion of a fuel to produce a pulsating flow of combustion products and an acoustic pressure wave. The pulse combustion device has a combustion chamber connected to at least one resonance tube. A resonance chamber surrounds at least a portion of the pulse combustion device and includes a nozzle downstream from the resonance tube. The nozzle accelerates the combustion products flowing therethrough and creates a pulsating velocity head. In a drying system, the nozzle exits into a drying chamber where the combustion products contact a feed stream. When used in a heating system, on the other hand, the nozzle exits into an eductor which mixes the combustion products with a recycled stream of combustion products for forming an effluent that is fed to a heat exchanging device.

Fuel heating system used in conjunction with steam cooled combustors and transitions

Abstract: A system is disclosed that provides for a more efficient combined cycle turbine system by using heated coolant returning from the gas turbine engine (40) to pre-heat fuel (25, 10) before that fuel is injected into the combustor (30). Coolant, such as steam, that is used to cool gas turbine combustors and/or transitions carries high grade heat energy that was removed from the top cycle. By returning the heat energy to the incoming fuel, energy is recovered at a more efficient rate than would result from recovering that heat energy in the bottom cycle.

A new concept of porous thermoelectric module using a reciprocating flow for cooling/heating system (numerical analysis for heating system)

Abstract: The paper presents the conceptual design of a novel thermoelectric cooler and/or heater utilizing the heat transfer effect due to forced convection. A porous thermoelectric converter combined with a reciprocating flow system in which the flow direction of air passing through the element is reversed after regular intervals is proposed. This flow system in effect makes the thermal conductivity insignificant and contributes toward the achievement of a highly efficient cooler and/or heater. A one-dimensional numerical analysis is performed to examine the detailed characteristics of the porous thermoelectric heater by systematically varying the relevant thermo-fluid parameters. In the calculation, for a fixed ambient temperature of 27/spl deg/C, dependences of the flow velocity, material porosity, and input power on the system performance are clarified. Moreover, a series of computation is carried out in order to obtain the system's COP.

Vehicle heating system

Abstract: An improved heating apparatus for a vehicle is disclosed. A water circuit circulates water to cool an engine. A viscous fluid type heater is disposed in a fluid circuit that is separately arranged from the water circuit. The heater has a heating chamber and a heat exchange chamber close to the heating chamber. The heat exchange chamber communicates with the fluid circuit. The heating chamber accommodates viscous fluid and a rotor rotatable to shear the viscous fluid for producing heat. The heat is transmitted to the heat exchange chamber from the heating chamber. The fluid in the heat exchange chamber is heated and flows to the fluid circuit.

Radiant floor heating system with reflective layer and honeycomb panel

Abstract: A radiant floor heating system and method of installation is provided, the system of the present invention being disposed within a solidified cement or under board A panel member having a laminated reflective material which serves as a thermal break is placed upon the hardened cement or under board The panel member may be comprised of any substance to which the reflective material may be secured such as a honeycombed plastic panel to which the reflective material layer is laminated A heating element is disposed on the reflective material Thereafter, both the heating element and the reflective layer are coated with a layer of thin set or cement The heating element may include a heated wire element which is unwound off a roll, or the heating element may be meshed within a web of material which is cut to match the dimensions of the floor and then disposed on top of the reflective layer After the thin set or cement dries with the heating element embedded within, marble or other types of tiles may be laid as flooring

Electric floor heating system

Abstract: An electrical heating system thin enough to be installed under finished flooring. A meshwork mat constructed in a leno configuration receives an electric heating element which is threaded through aligned openings in the twisted strands of the warp strands. The strands of the mat and the intersections between the criss-crossing warp and weft strands are coated with a polymeric fusing material. The heating element is arranged in side by side runs to minimize the electromagnetic field effects. Connecting runs between adjacent pairs of side by side runs are arranged linearly end to end. A return wire is extended adjacent to and side by side with the connecting runs.

Zone heating system with feedback control

Abstract: A structure and method are disclosed which allow for a tighter control of the temperature across a wafer substrate. In accordance with the present invention, a wafer (16) to be processed is heated to a constant and uniform temperature by an RF induction coil (18,20) including a plurality of heating zones each of which being shunted by an associated capacitor tuned to a specific frequency. By adjusting the time during which current of a particular frequency is provided to the induction coil, current flow within, and thus the heat generated in, each of the zones may be independently controlled. Since the heat generated in the susceptor quickly changes in response to changes in current flow therein, both deviations of the wafer temperature from the processing temperature and temperature gradients across the surface of the wafer may be quickly corrected. This superior thermal response results in the present invention maintaining a wafer at a uniform temperature during heating and cooling with increased accuracy and precision.

Tractor trailer temperature control for tractors with refrigerated trailers

Abstract: A tractor heating system for heating the cabin of a tractor wherein the tractor is carrying a refrigerated trailer. The heating system includes a feed duct in communication with a refer cooling system and the heater of the tractor for communicating heated fluid from the refer cooling system to the heater for heating the tractor cabin. A return duct returns fluid from the tractor heater to the refer cooling system wherein heated fluid from the refer cooling system may be utilized by the tractor heating for heating the cabin of the tractor and also the tractor engine.

Apparatus and method for heating a ground surface or volume of air with a portable hot water-type heating system

Abstract: A flexible fluid-filled circulation conduit is selectively and removably connectable to a portable hot water heating system. The conduit is configured and arranged so that prior to connection to the hot water heating system, the conduit carries its own fluid supply under pressure within the conduit for circulation through the hot water heating system. Upon removable connection of the fluid filled conduit to the hot water heating system, fluid from the conduit immediately circulates under pressure with fluid from the hot water heating system through both the conduit and hot water heating system. Upon selective disconnection of the conduit from the hot water heating system, fluid within the conduit is retained under pressure within the conduit and fluid continues to circulate through the hot water heating system but is prevented from circulating through the conduit. With this system, fluid need not be directly added or removed relative to the hot water heating system to accommodate adding or removing the conduit relative to the hot water heating system circulation loop. This system can be used in a method of thawing frozen ground or of providing temporary heat within a building.

Induction heaters to improve transitions in continuous heating systems, and method

Abstract: A heating system (50) and method for heating a metal strip (40) to within a predetermined temperature tolerance range while the metal strip (40) serially travels through the heating system (50). The heating system (50) has at least one preceding heating section (52), at least one induction heating section (54), and at least one following heating section (56), with the heating sections (52, 54, 56) being serially arranged. The metal strip (40) is heated to below the Curie point of the metal strip (40) in the preceding heating section (52). Next, the metal strip (40) is heated to, at a maximum, approximately the Curie point in the induction heating section (54). Then, the metal strip (40) is heated to above the Curie point and to within the predetermined temperature tolerance range in the following heating section (56).

An Analysis of the Performance of Different Intermittent Heating Controllers and an Evaluation of Comfort and Energy Consumption

Abstract: This article presents a new controller, based on fuzzy logic, to be used for the control of heating systems in intermittently occupied buildings. Its originality lies in the fact that it takes into account the thermal state of buildings, as well as the outside temperature. The TRNSYS simulation software was used to model a multizone building, its hot-water-radiator heating system, and a several types of thermal control. The controller was tested for different configurations of thermal inertia, excess plant capacity, internal loads, and set-point temperature for periods when unoccupied. Comparisons with classical control methods were used to demonstrate that the fuzzy controller gave superior results in terms of the control and optimization of the recovery time after setback. For each case, the differences in comfort and energy consumption between the different types of room were studied.

A methodology for thermal analysis and predictive control of building envelope heating systems

Abstract: A heating system integrated into the building envelope, such as a floor radiant heating system, is defined as a building envelope heating system (BEHS). Thermal mass usually integrated with such a heating system can be utilized to lower both peak loads and operating costs and to reduce room temperature swings by predictive control while utilizing solar gains to reduce energy consumption. Nevertheless, techniques required for the predictive control of BEHSs need to be developed in order to materialize these potential benefits. A methodology proposed in this study integrates building thermal analysis and predictive control of BEHS. A computer method for generating the symbolic transfer function of buildings is developed as the first part of the methodology. It includes hybrid signal flowgraph and generalized-nodal admittance formulations, and an algebraic algorithm associated with the constraint conditions of inequalities. New concepts for thermal network modelling are presented, with which a combined thermal parameter such as the operative temperature can be explicitly represented with an imaginary thermal network. A building thermal system is systematically modelled with a generalized thermal network. Because some design parameters of interest, such as amount of thermal mass, can be kept as symbols in the model, sensitivity analysis, optimum design and control studies of building systems can be significantly facilitated. An optimal predictive control system developed integrates a weather predictor, set-point optimizer, a system identifier and an adaptive Generalized Predictive Control algorithm so as to achieve high building thermal performance. A new weather predictor, simplified through normalization, makes it feasible to quantify the qualitative weather forecast for solar radiation. Several implementation issues in on-line parameter estimation are investigated through experiments in an outdoor passive solar test-room. A Generalized Predictive Controller (GPC) with a feedforward control scheme is improved with a new algorithm. The zone set-point is optimized through the combination of dynamic programming and on-line simulation. The methodology has been verified with both experiments and simulations. Results show that the weather predictor is capable of generating reasonably accurate solar radiation and outdoor temperature profiles for one day. A building thermal model can be robustly identified under the supervision rules. The performance of GPC is superior to conventional on-off and PI controllers. The optimal set-point can be efficiently generated by the proposed approach, which may lead to large savings in operating energy costs when a BEHS is properly designed and operated.

Heating system especially for electric cooking operations

Abstract: The heating system for electric cooking operations has at least one cooking ring (12) with an electric heating unit (14), and with a vessel, the contents of which are to be heated. The heating unit has facilities (15) for transmitting inductive fields. The vessel has at least one insert element, which at least partly consists of at least one material with ferromagnetic characteristics. This material has a Curie temperature, which lies in the region of at least one limit temperature, which is provided for the vessel (22) and/or its contents. Means (16) are provided for the alternation, especially for switching off, the heating power of the heating unit (14). The insert element (23) for determined characteristics consists of several ferromagnetic material with different Curie temperatures.

Method and device for controlling operation of heat pump

Abstract: A method and device for controlling the operation of a heat pump having a primary heat system and an auxiliary heat system, and used to heat air circulating in an enclosure such as a building, the invention comprising a first sensor positioned in the return duct of the heating system for measuring the temperature of air being returned to the heat system from the enclosure, a second sensor for measuring the temperature of air which has been heated only by the primary heat system, a temperature comparing relay for comparing the two sensed temperatures and determining the difference between them and actuating the auxiliary heat system only when the temperature difference is less than a predetermined set point, for example 4° F., thereby providing a significantly enhanced operating efficiency of the heating system.

A neural network prototype for fault detection and diagnosis of heating systems

Abstract: An artificial neural network (ANN) prototype for fault detection and diagnosis (FDD) in complex heating systems is presented in this paper. The six operating modes with faults used to develop this prototype stemmed from a detailed investigation in cooperation with heating systems maintenance experts, and are among the most important operating faults for this type of system. The prototype has been developed by using the daily values obtained by a preprocessing procedure of the simulation data of one reference heating system, and then generalizing to four heating systems not used during the training phase. This paper demonstrates the feasibility of using ANNs for detecting and diagnosing faults in heating systems provided that training data representative of the behavior of the systems with and without faults are available.

Turbomachine for non-perfect gas

Abstract: The turbo-compressor has a dry gas seal with slip rings (24,25) which prevent gas leaks to atmosphere under normal working conditions. If the compressor is stopped and the gas temperature falls, due to the Joule-Thompson effect, then a heating system (18) prevents the gas seal from cooling too much. This prevents undue loss of gas, or loss of a sealant gas. The heating system is also activated when the gas pressure rises above a set level, eg. 100 bar. The heating system has a duct (18c) for a heated coolant, which can be a different fluid than the gas, and has a heating element near to the gas seal.

Heat transfer optimization of a district heating system using search methods

Abstract: This study investigates the parameters that allow for the effective use of district heating. A basic objective of this study was to find a method for optimizing the location for the installation of satellite boilers based on eliminating high energy losses in the piping. This was achieved employing the Jacksonville Naval Air Station (NAS) as a study model and using a search method utilizing a standard computer spreadsheet program. Use of a computer spreadsheet to perform search methods allows all probable locations for satellite boilers to be analysed in order to find the optimum location or combination of locations to maximize savings. The annual cost of energy lost in the piping eliminated by using satellite boilers was compared to the additional annualized capital investment of satellite boiler installation. The study found that satellite boilers could save energy and costs if located where the demand was high and if separated by long distances from the district heating plant.

Dynamic modeling and global optimal operation of multizone variable air volume HVAC systems

Abstract: Energy conservation and indoor environment concerns have motivated extensive research on various aspects of control of Heating, Ventilating and Air-Conditioning (HVAC) and building systems. The study on optimal operation as well as modeling of HVAC and building systems is one of the fastest growing fields that contribute to saving energy and improving indoor environment. This thesis is devoted to the development of a comprehensive modeling and optimization methodology for global multiple-stage optimal operation of HVAC and building systems. Two different dynamic models of a multizone variable air volume (VAV) system have been developed using (i) bottom-up and (ii) top-down approaches. The models take account of the dynamic interactions between building shell, VAV system components and control systems. The models describe the dynamics of fan, air distribution system, zone(s), cooling coil and primary plant (chiller) as one multivariable nonlinear system in a way that is useful for control analysis. Using the bottom-up approach a large-scale VAV system model has been developed. This model considers the interactions between flow field and thermal field via distributed capacity and variable air density considerations. An alternate model which is computationally more efficient was developed using the top-down approach. Model reduction techniques were applied to develop a reduced-order state space model of the VAV system. Results show that predictions from the reduced order model are within 5% of those from the large scale model. Optimal control schemes are developed for the efficient operation of VAV systems. In the control scheme proposed it is necessary to compute optimal setpoint profiles for local controllers. The optimal control profiles so computed can be used as tracking signals for local controllers for moving the system states from one setpoint to another. In order to determine optimal setpoint profiles an optimization methodology for formulating and solving the multiple stage optimal operation problems has been developed. The methodology is based on the maximum principle of Pontryagin and perturbation method in order to deal with the multiple time-scale of the HVAC processes and building operating schedules. A solution methodology and the corresponding computer models have been developed for solving the multiple stage optimal operation problems. The applications of the VAV model and the multistage optimization methodology have been demonstrated by considering several practical examples. The examples include (i) a comparison of optimal strategies for constant and variable air volume systems with and without time-of-day price structure for electrical energy, (ii) a two-zone VAV heating system and (iii) a five-zone VAV cooling system. Results showing the 24-hour optimal setpoint profiles, energy cost savings and the output responses such as zone temperatures and humidity ratios are given for different building operation schedules. These applications show that the developed models and optimization methodology can be used to determine energy efficient operating strategies for VAV systems without violating the thermal comfort in buildings.

Hot-water heating system

Abstract: A hot-water heating system has a heater for producing hot water, a heat radiator, a supply pipe for supplying them hot water from the heater to the heat radiator, a return pipe for returning the heat radiator to the heater, and a circulation pump for circulating the hot water from the heater successively through the supply pipe, the heat radiator, and the return pipe. A supply pipe temperature sensor for detecting the temperature of the hot water flowing through the supply pipe is mounted on an outer surface of the supply pipe. A return pipe temperature sensor for detecting the temperature of the hot water flowing through the return pipe is mounted on an outer surface of the return pipe. A control unit controls the circulation pump to reduce an output rate thereof as the difference between the temperatures of the hot water detected by the supply pipe temperature sensor and the return pipe temperature sensor is reduced.

On-line genetic algorithm tuning of a PI controller for a heating system

Abstract: Genetic algorithms have been used successfully for a number of off-line control optimisation problems This paper investigates their use for the online regulation of temperature in a bench top heating system Two approaches are considered: 1) using a time-invariant model of the plant dynamics with the GA adaptively choosing the PI controller parameters; 2) extending the idea using a time varying estimate of the plant model Test results are given for both methods The paper concludes that the approach offers good regulation and good promise for application to more complex multivariable systems

Solar heating control system e.g. for water

Abstract: The system has a solar panel (10) to heat a transfer liquid which is pumped by pump (20) around a circuit containing a heat exchanger (14), and a heating coil inside a water storage tank (16). The stored water is heated and provides a source of hot water or for powering a heating system. Temperature sensors (24,28,34) monitor the temperature of the transfer liquid into and out of the heating coil as well as the temperature of the solar panel. A control unit (40) operates the circulating pump as required. The control unit determines if thermal energy is to be transferred between the solar panel and the heating circuit and operates the pump accordingly. The pump only operates as long as there is an effective heat transfer to the storage tank and is switched off when no heat can be transferred. There is no temperature sensor required for the tank itself.