Energy efficiency and indoor thermal perception: a comparative study between radiant panel and portable convective heaters

Abstract

This study investigates experimentally the thermal perception of indoor environment for evaluating the ability of radiant panel heaters to produce thermal comfort for space occupants as well as the energy consumption in comparison with conventional portable natural convective heaters. The thermal perception results show that, compared with conventional convection heater, a radiantly heated office room maintains a lower ambient air temperature while providing equal levels of thermal perception on the thermal dummy head as the convective heater and saves up to 39.1% of the energy consumption per day. However, for human subjects' vote experiments, the results show that for an environmentally controlled test room at outdoor environment temperatures of 0°C and 5°C, using two radiant panel heaters with a total capacity of 580 W leads to a better comfort sensation than the conventional portable natural convective heater with a 670 W capacity, with an energy saving of about 13.4%. In addition, for an outdoor environment temperature of 10°C, using one radiant panel heater with a capacity of 290 W leads to a better comfort sensation than the conventional convection heater with a 670 W capacity, with an energy saving of about 56.7%. From the analytical results, it is found that distributing the radiant panel heater inside the office room, one on the wall facing the window and the other on the wall close to the window, provides the best operative temperature distribution within the room. Keywords Energy efficiency . Radiant panel heater . Conventional natural convective heater . Indoor environment thermal perception . Energy saving Nomenclatures Alphabetic Symbols A surface area, m 2 c p specific heat, J/kg K F radiation configuration (shape) factor h heat transfer coefficient, W/m 2 K H room height, m Á m mass flow rate, kg/s N number of surface elements number, -q heat flux, W/m 2 Q heat transfer, W R th thermal resistance, m 2 K/ W T temperature, K or°C X axial horizontal distance, m, -y axial vertical distance, m, -Z axial distance, m, -Greek Symbols ε emittance ρ reflectance σ Stefan-Boltzmann constant, (5.67051×10 -8 ),

Annual performance analysis of heat emission in radiator and underfloor heating systems in the European reference room.

“…The European standard EN 15316 [6] proposes an approach that tries to quantify the effect of different components of the system, e.g. the room air stratification due to the emitter system, the control accuracy of the system due to imperfect control, and the effect of the system on thermal comfort, which is expressed by the operative temperature [6,7,8,9]. This quantification takes the form of additive set-point increments to the initial room air temperature set-point, to account for the additional energy needed to overcome the effects of these components.…”

Optimization of Radiators, Underfloor and Ceiling Heater Towards the Definition of a Reference Ideal Heater for Energy Efficient Buildings

“…), each determining the energy demand in a specific way [4][5][6][7][8]. For these reasons, several studies have investigated the emitters' performance on both the experimental and theoretical viewpoint [9][10][11], focusing especially on the design, specific type and room placement of panel radiators (e.g., close to a window or slightly detached from a wall) [4,[12][13][14][15][16][17][18]. For instance, measurements have shown a better performance of low temperature panel radiators [19], and a sensibly different outcome for serial and parallel connected radiators [9].…”

Optimization of Radiators, Underfloor and Ceiling Heating towards the Definition of a Reference Ideal Heater for Energy Efficient Buildings

“…For these reasons, several studies have investigated the emitters performance on both the experimental and theoretical viewpoint [9][10][11], focusing especially on the design, specific type and room placement of panel radiators (e.g. close to a window or slightly detached from a wall) [4,[12][13][14][15][16][17][18]. For instance, measurements have shown a better performance of low temperature panel radiators [19], and a sensibly different outcome for serial and parallel connected radiators [9].…”

“…Nevertheless, since heating consumption is nowadays assessed in function of thermal comfort, the so-called operative temperature (op.t.) t op is being increasingly used [9,13,18,20]. This is defined as the uniform temperature of an enclosure in which an occupant would exchange the same amount of heat by radiation and convection as in the existing non-uniform environment [21].…”