The School of Architecture of the University of Navarra has begun a project which consists in
constructing a prefabricated module, consisting of a simplified inhabited housing unit, and monitoring
over the course of one year the behavior of a thermoelectric installation that provides service to this
module.
The principal objective of the project is to quantify the response capacity of a thermoelectric climate
control system applied to a prototype, and evaluate its energy and economic costs in the case that the
system were applied in an apartment building.
The development of this project represents the application in the field of construction of a technology
that already is in use in other areas, fundamentally the military and aerospace. Therefore, we do not
seek to demonstrate the performance of Peltier cells per se, but rather to evaluate how they function
when applied to the residential area, and to analyze both the positive and negative aspects of their use

Eguaras-Martínez, M. (María)

Mambrilla-Herrero, N. (Natalia)

Martín-Gómez, C. (César)

Ramos-González, J. (Juan Carlos)

Rivas, A. (Alejandro)

Torres-Ramo, J. (Joaquín)

The School of Architecture of the University of Navarra has begun a project which consists in constructing a prefabricated module, consisting of a simplified inhabited housing unit, and monitoring over the course of one year the behavior of a thermoelectric installation that provides service to this module.
The principal objective of the project is to quantify the response capacity of a thermoelectric climate control system applied to a prototype, and evaluate its energy and economic costs in the case that the system were applied in an apartment building.
The development of this project represents the application in the field of construction of a technology that already is in use in other areas, fundamentally the military and aerospace. Therefore, we do not seek to demonstrate the performance of Peltier cells per se, but rather to evaluate how they function when applied to the residential area, and to analyze both the positive and negative aspects of their use.
In this regard, it must not be forgotten that Spanish regulations also require the evaluation of the maintenance needs of climate control equipment, and, in this regard, Peltier cells offer an important
advantage: Despite the fact that the initial investment is greater than with a conventional method of climate control, the maintenance costs are nearly zero.
For these reasons, an objective of the project is to estimate the construction and amortization costs of the application of this technology in the residential area

Universidad de Navarra

Prototype Thermoelectric Climate System for its Use in Residential Buildings

Dadun, University of Navarra

XXXVII IAHSWorld Congress on HousingOctober 26 – 29, 2010, Santander, SpainXXXVII IAHS – PROTOTYPE THERMOELECTRICCLIMATE SYSTEM FOR ITS USE IN RESIDENTIALBUILDINGSCésar Martín Gómez a, María Eguaras a, Natalia Mambrilla a, Joaquín Torres a, Juan CarlosRamos b, and Alejandro Rivas baDepartment of Construction Science – Installations and EnergyaUniversidad de Navarraae-mail: instetsaun@unav.esbDepartment of Mech. Engineering, Thermal and Fluids Engineering DivbTECNUN (Universidad de Navarra)be-mail: jcramos@tecnun.es / arivas@tecnun.esKey words: Architecture, HVAC, thermoeletric, residential, efficiency.AbstractThe School of Architecture of the University of Navarra has begun a project which consists inconstructing a prefabricated module, consisting of a simplified inhabited housing unit, and monitoringover the course of one year the behavior of a thermoelectric installation that provides service to thismodule.The principal objective of the project is to quantify the response capacity of a thermoelectric climatecontrol system applied to a prototype, and evaluate its energy and economic costs in the case that thesystem were applied in an apartment building.The development of this project represents the application in the field of construction of a technologythat already is in use in other areas, fundamentally the military and aerospace. Therefore, we do notseek to demonstrate the performance of Peltier cells per se, but rather to evaluate how they functionwhen applied to the residential area, and to analyze both the positive and negative aspects of their use.In this regard, it must not be forgotten that Spanish regulations also require the evaluation of themaintenance needs of climate control equipment, and, in this regard, Peltier cells offer an importantadvantage: Despite the fact that the initial investment is greater than with a conventional method ofclimate control, the maintenance costs are nearly zero.For these reasons, an objective of the project is to estimate the construction and amortization costs ofthe application of this technology in the residential area.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        1 IntroductionThe Thermoelectric Conditioning System (TCS) is designed to reach a high confort level for peopleliving in the local. Without mechanical parts like pumps or compressors, there is no necessity formaintenance, reducing the possibilities of failures. The only mechanical elements are the dissipationheat fans placed in the external face of the prototype. There are also some minifans to evacuate theheat from the power elements.Currently, the prototype is being constructed in the School of Architecture of the Universidad deNavarra, according with the following plan:Figure 1: Prototype building considerations.Nevertheless, the optimistic architectural results have made possible the start of the necessary patentsteps. So the authors can not show in these moments the technological interior of the interior but asketch with its dimensions and main characteristics.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        Figure 2: Prefabricated module in the School of Architecture of the Universidad de Navarra.Figure 3: Prototype external view and dimensions.Characteristics:- Power consumption: 30 A- Heat transfer capacity: 3 kW- Number of Peltier cells: 42 (Marlow Industries, Inc)- Manufacturer: Berotza (Spain)The TCS is compact, and it is only necessary a reserve space in the building façade for its collocationas an prefabricated element. The external view is for the metallic frame with the dissipation fans andthe air grills. The TCS internal view (from the user’s point of view) is an aluminium surface, with thefiltration air system and the adjustable air exit grill.The TCS dissipation elements (before the external fans) are made using heat-pipe technology, whichresult is an important rise in the heat dissipation capacity reducing the surface necessities. In this waythe air-flow is lower and so the noise level. This technology determines the vertical TCS positiondesign. Power units that serve the TCS are placed on the external dissipation heat side.In the local interior there is an electric board with the protection elements necessaries for its running.These elements are connected to the monitoring and control system. The electric supply is 230 Vsingle-phase with an 30 A estimated consume in the maximum operational mode.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        2 Mathematical modelling and simulating2.1 Approaching the problemSome earliest approaches to modelling the thermal behaviour of our housing module haveinvolved the analysis of several simple case studies simulating every specific aspect of theoverall thermal behaviour. Those have been done by the finite volume method, using StarCCM+, a commercial software of computational fluid dynamics (CFD) developed by Adapco.These case studies allow us a separate analysis for each one of the processes of heat transfer.Figure 4: Case Study 1. Stationary one-dimensional conduction through a homogeneous solid.               Figure 5: Case Study 2. Mechanically forced convection.Figure 6: Case Study 3. Direct and diffuse solar radiation at a time throughout the day.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        2.2 Full ModelFlow domainA single and homogeneous fluid is considered. (Euler flow domain). Boundary conditions arestated (Dirichlet condition).The space modelled is a parallelepiped shape of 600 x 240 x 260 cm (length x width x height).Its faces are defined bellow:Table 1: Dimensions and orientation of the moduleSurface Orientation Dimensions (cm) Area (m2)Façade 1 N 240 x 260 6,24Façade 2 S 240 x 260 6,24Façade 3 E 600 x 260 15,60Façade 4 O 600 x 260 15,60Ceiling - 600 x 240 14,40Floor - 600 x 240 14,40One inlet and an outlet air surface are defined on the south side. These allow simulating thethermal input from the Peltier cells panel. An area of 3.12 m2 is also defined as a glazed area.An orthogonal structured mesh is chosen because of model geometry. Cell size becomessmaller near the walls and near the holes that allow openings and exhaust.Figure 7: Orthogonal structured mesh.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        Starting conditions: Outside air temperature 35ºC Indoor temperature 15ºCInside air temperature is considered pleasant in 25°C.Boundary conditions:  Facades, roof and floor are `walls´. Every coefficient of thermal conductivity for globaltransmittance is defined for each enclosure. The sidewalls of cylinders are considered adiabatic.  The area of the air outlet is defined as velocity inlet: velocity flow and temperature arestated. The area of air return is defined as outlet pressure.Definition of physical model (continua) A three dimensional model. Steady state flow. Air is considered as an ideal gas. Gravity is added to consider the natural convection behaviour of inside air.  Phenomena of solar radiation, setting azimuth and latitude values, considering the fronttwo facing south. k-ε turbulence model.2.3 Analysis of resultsDiverse parameters are studied in order to interpret the results through the following figures:Figure 8: Temperature distribution in the X-Z plane (inside temperature).                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        Figure 9: Temperature distribution on the inner surfaces.Figure 10: Temperature values on the outer surfaces due to solar radiation.Figure 11: Residual and convergence error control (criteria).In more advanced steps of the research, we propose the comparison of experimental data(which may have some measurement error) and those obtained by CFD (where error is due tothe modelling). The analysis of these results allows evaluating new corrections or greaterprecision in the calculations in order to improve the façade panel.                                        XXXVII IAHS, Octobre 26-28, 2010, Santander (Cantabria). Spain                                        3 Engineering DevelopmentThe description of this development has been detailed in the 2010 29th International Conference onThermoelectrics Proceedings Book published by the “29th International Conference onThermoelectrics” (May 30 - June 3, 2010. Shanghai, China).4 ConclusionsThis paper has developed the methodology for the theoretical study of a prototype thermoelectricclimate system for the residential area. The exact development of this methodology is necessary,because the next steps of the research are orientated to the comparison between these theoretical data,and the results taken during the monitoring of the prototype build in the School of Architecture of theUniversidad de Navarra.In this way, these initial considerations about the Peltier system behaviour is helping the research teamto take important design decisions for the prototype building.Finally, depending upon the results obtained, it will be proposed that the project be concretized in apatent for a "prefabricated and decentralized facade module for the climate control of inhabited spaces".References- Arenas, A. “Determinación de Nuevos Criterios que permitan la optimización de Parámetros deDiseño de una Bomba de Calor por Efecto Peltier”. Departamento de Ingeniería Mecánica. Madrid,Universidad Pontificia Comillas. 1999- Arenas, A., Pagola F. L., Palacios, R., Rodríguez, P., Vázquez, J., “Paramento transparente activo(PTA) en aplicaciones de climatización”, Revista de Edificación, Escuela de Arquitectura de laUniversidad de Navarra, 2007, pp. 100-109.- López, A, Noriega, G.F., Redondo, J.M., Villasevil, F., “Introducción a la termoelectricidad”.- Sanz-Bobi, M.A., Palacios, R., Villar, J., Arenas, A., “Prototipo de Bomba de Calor por EfectoPeltier para Aplicaciones de Climatización”. Anales de la Ingeniería Mecánica. Año 9, vol.3, 1992, pp.251-253.- Semeniuk, V. “Thermoelectric Cooler as a Component of Electro-Optic Device: System Approach”,19th International Conference on Thermoelectrics, Cardiff, UK, 2000, pp. 289-295.- Vázquez, J., et al. “An Active Thermal Wall base don Thermoelectricity”, 6th European Workshopon Thermoelectrics, Freiburg, Germany, 2001, pp. 70-77.- Vázquez, J., Palacios, R., Sanz-Bobi, M.A., Arenas, A., “Termoelectricidad y sus aplicaciones enbombeo de calor”. Ibérica Actualidad Tecnológica, 2001, pp.97-105.- Williams, S. G. K., et al. “Improved Thermoelectric Modules for Electrical Power Generation UsingLow Temperature Waste Heat”, 5th European Workshop on Thermoelectrics, Pardubice, CzechRepublic, 1999, pp. 93-98.

PROTOTYPE THERMOELECTRIC CLIMATE SYSTEM FOR ITS USE IN RESIDENTIAL BUILDINGS

PROTOTYPE THERMOELECTRIC CLIMATE SYSTEM FORITS USE IN RESIDENTIAL BUILDINGSCésar Martín Gómez a, Juan Carlos Ramos b, Alejandro Rivas b, María Eguaras a, NataliaMambrilla a, Joaquín Torres aaDepartment of Construction Science – Installations and EnergyaUniversidad de Navarraae-mail: instetsaun@unav.esbDepartment of Mech. Engineering, Thermal and Fluids Engineering DivbTECNUN (Universidad de Navarra)be-mail: jcramos@tecnun.es / arivas@tecnun.esKey words: Architecture, HVAC, thermoeletric, residential, efficiency.AbstractThe School of Architecture of the University of Navarra has begun a project which consists inconstructing a prefabricated module, consisting of a simplified inhabited housing unit, and monitoringover the course of one year the behavior of a thermoelectric installation that provides service to thismodule.The principal objective of the project is to quantify the response capacity of a thermoelectric climatecontrol system applied to a prototype, and evaluate its energy and economic costs in the case that thesystem were applied in an apartment building.The development of this project represents the application in the field of construction of a technologythat already is in use in other areas, fundamentally the military and aerospace. Therefore, we do notseek to demonstrate the performance of Peltier cells per se, but rather to evaluate how they functionwhen applied to the residential area, and to analyze both the positive and negative aspects of their use.1 IntroductionIn this regard, it must not be forgotten that Spanish regulations also require the evaluation of themaintenance needs of climate control equipment, and, in this regard, Peltier cells offer an importantadvantage: Despite the fact that the initial investment is greater than with a conventional method ofclimate control, the maintenance costs are nearly zero.For these reasons, an objective of the project is to estimate the construction and amortization costs ofthe application of this technology in the residential area.Finally, depending upon the results obtained, it will be proposed that the project be concretized in apatent for a "prefabricated and decentralized facade module for the climate control of inhabited spaces".The Thermoelectric Conditioning System (TCS) is designed to reach a high confort level for peopleliving in the local. Without mechanical parts like pumps or compressors, there is no necessity formaintenance, reducing the possibilities of failures. The only mechanical elements are the dissipationheat fans placed in the external face of the prototype. There are also some minifans to evacuate theheat from the power elements.Currently, the prototype is being constructed in the School of Architecture of the Universidad deNavarra, according with the following plan:[Fig. 1]Nevertheless, the optimistic architectural results have made possible the start of the necessary patentsteps. So the authors can not show in these moments the technological interior of the interior but asketch with its dimensions and main characteristics.[Fig. 2]Characteristics:- Power consumption: 30 A- Heat transfer capacity: 3 kW- Number of Peltier cells: 42 (Marlow Industries, Inc)- Manufacturer: Berotza (Spain)The TCS is compact, and it is only necessary a reserve space in the building façade for its collocationas an prefabricated element. The external view is for the metallic frame with the dissipation fans andthe air grills. The TCS internal view (from the user’s point of view) is an aluminium surface, with thefiltration air system and the adjustable air exit grill.The TCS dissipation elements (before the external fans) are made using heat-pipe technology, whichresult is an important rise in the heat dissipation capacity reducing the surface necessities. In this waythe air-flow is lower and so the noise level. This technology determines the vertical TCS positiondesign. Power units that serve the TCS are placed on the external dissipation heat side.In the local interior there is an electric board with the protection elements necessaries for its running.These elements are connected to the monitoring and control system. The electric supply is 230 Vsingle-phase with an 30 A estimated consume in the maximum operational mode.2 Engineering Development2.1 DESCRIPTION OF the systemThe inhabited space modelled has a cubic shape with edges of 2 m length. The four walls, the floorand the ceiling are of concrete (thermal conductivity 1.8 W/m K) with 20 mm of thickness. In one ofthe walls there are 4 Peltier cells model ET-241-14-15-RS with internal and external heat sinks of 0.25m2 of equivalent heat transfer surface area. The parameters of the Peltier cells are: electric resistance,Re = 3.81 Ω; thermal resistance, Rt = 1.31 K/W; Seebeck coefficient, α = 0.09 V/K.[Fig. 3]2.2 MATHEMATICAL MODELThe natural convection of the air inside the described enclosure can be studied solving thegoverning differential equations restricted to the boundary conditions inside the modelled flowdomain.2.2.1 Governing EquationsThe Reynolds Average approach of the Navier-Stokes (RANS) equations, (1) and (2), and theEnergy equation (3) is used to include turbulence effects in the mean flow variables. The buoyancyterm has been included in the right side of equation (2) to take into account the movement provoked bydensity variations of the air. The air is modelled as ideal gas and its properties are temperaturedependent.( ) 0=⋅∂∂iiUxρ (1)( ) ( ) ( )032ρρδρµµρ −⋅−⎥⎥⎦⎤⎢⎢⎣⎡⋅⋅⋅−⎟⎟⎠⎞⎜⎜⎝⎛∂∂+∂∂⋅+∂∂+∂∂−=⋅⋅∂∂iijijjiTjijijgkxUxUxxPUUx (2)( ) ( ) ⎥⎦⎤⎢⎣⎡∂∂⋅+∂∂=⋅⋅⋅∂∂iTipii xTxTcUxλλρ (3)Turbulence is modelled using the Standard k-ε turbulence model which introduces two additionalequations, one for the turbulent kinetic energy and other one for its dissipation rate. The standard wallfunctions approach has been adopted to deal with turbulence near the walls. The turbulent eddy andthermal diffusivity are calculated solving eqs. (4), with a constant value of C_ = 100, and (5), with aconstant value of PrT = 0.85, respectively:21 ⎥⎦⎤⎢⎣⎡⋅⋅+⋅=εµρµµ νkCT (4)TTpT Prc µλ⋅= (5)The radiation heat exchange is considered by means of the Discrete Ordinates (DO) model whichis solved once every ten ordinary iterations. It has been assumed that the air does not participate in theradiation and that the different surfaces in the domain are gray and diffuse.2.2.2 Flow DomainThe flow domain of the model corresponds to the air inside the room. A high quality hexahedralmesh has been used in the discretization of the flow domain. The number of cells is of the order of500,000. The resolution of the mesh is higher in the near wall region so as to capture the largermagnitude gradients that take place there.2.2.3 Boundary ConditionsThe surfaces of the walls of the room, including floor and ceiling, are modelled as solid walls withone-dimensional heat conduction. In the outer side of these external walls convective boundaryconditions are considered with an ambient temperature of 15 ºC and a heat transfer coefficient of 5W/m2 K. In the inner side of the walls the emissivity has been fixed to a value of 0.9.In conjunction with these thermal boundary conditions, a non-slip condition is ascribed to fluidvelocity at all the solid walls, and the shear stress is calculated considering smooth surfaces.In the surfaces representing the internal heat sinks of the Peltier cells the equations that representtheir mathematical model have been implemented in order to calculate the heat transferred by them tothe air inside the room. These equations, (6)-(8), relate the power consumption of the cell, P, with theheat dissipated to the hot environment, qhot, and the heat extracted from the cold reservoir, qcold.ecoldhot RITTIP  ) ( 2+−=α (6)tcoldhotehothot RTTRITIq )(  21   2−−+=α (7)tcoldhotecoldcold RTTRITIq )(  21   2−−−=α (8)The resolution of the former equations is coupled to the equations describing the air movementand the heat transfer inside the enclosure.2.2.4 Discretization and ResolutionThe Finite Volume Method (FVM ) is applied to discretize the differential equations of themathematical model described above, using a segregated implicit solver to solve the generatedalgebraic equation system. Therefore, equations are linearised and then sequentially solved using theGauss-Seidel algorithm accelerated by an Algebraic Multigrid method [17]. The pressure-velocitycoupling is achieved through the use of the SIMPLE algorithm [18]. Diffusive terms of the equationsare discretized using a second-order centred scheme, and the convective terms are discretized using asecond-order upwind scheme [16]. A body force weighted scheme [19] is chosen in the discretizationof pressure to deal with this buoyancy-driven flow. All this numerical procedure has beenimplemented in the unstructured CFD code Fluent V.6.3 [20].2.2.5 Convergence CriteriaThree main convergence criteria have been applied to determine when the numerical proceduredescribed in the previous paragraph has converged to a solution. The first criterion consists of reachingperdurable values for the temperatures in the surfaces representing the Peltier cells, meaning that aconverged steady state has been reached. The second criterion is the balance between the energydissipated by the Peltier cells and the energy losses through the walls of the space. The final criterionis to check that the values for the scaled residuals of the equations are below certain magnitudes: 10-3for the mass, momentum and turbulent equations and 10-6 for the energy equation.2.3 RESULTSHeat dissipated by each Peltier cell to the room: 68 W.Power consumption by each Peltier cell: 46 W.[Fig. 4][Fig. 5][Fig. 6][Fig. 7][Fig. 8]3 Simulation model of prefabricated moduleThe description of this simulation will be detailed in the XXXVII - IAHS WORLD CONGRESS ONHOUSING SCIENCE: DESIGN, TECHNOLOGY, REFURBISHMENT AND MANAGEMENT OFBUILDINGS 2010.Figure 1: Prototype building considerations.Figure 2: Prototype external view and dimensions.Peltier CellsFigure 3. Cubic inhabited space with 4 Peltier cells in one side wall.Figure 4. Temperature contours on the surface of the Peltier cells.Figure 5. Air temperature contours in a central plane normal to the wall with the Peltier cells.Figure 6. Air temperature contours in a central plane parallel to the wall with the Peltier cells.Figure 7. Air temperature contours in a horizontal central plane normal to the wall with the Peltiercells.Figure 8. Air temperature contours in a plane cutting two of the Peltier cells.

PROTOTYPE THERMOELECTRIC CLIMATE SYSTEM FOR ITS USE IN RESIDENTIAL BUILDINGS

Abstract

Similar works

Full text

Available Versions

Universidad de Navarra

Dadun, University of Navarra

Universidad de Navarra

Dadun, University of Navarra