Controlling the Thermal Power of a Wall Heating Panel with Heat Pipes by Changing the Mass Flowrate and Temperature of Supplying Water—Experimental Investigations

Abstract

Renewable energy sources for the purpose of heating buildings cooperate perfectly with so-called low-temperature heating systems. Water loop surface heating systems had been thoroughly tested. In contrast, thermal performance of wall panels with heat pipes have not been fully recognized, yet. The determination of the thermal power as well as the control of panels thermal performance cannot be performed with the methods developed for water loop systems. In this paper, the novel heating panels with heat pipes were tested to analyze the possibility of controlling their performance by changing the mass flowrate of heating water and its temperature. Specific heating power of the investigated panels varies from 16.9 W/m2 to 93.8 W/m2 when supplying a water temperature ranging from 35 °C to 65 °C and mass flowrate from 10 g/s to 47.5 g/s. Investigations revealed that the thermal performance of the panels is more sensitive to the changes of temperature than to the changes of mass flowrate of supplying water, and thus, should be controlled by changing the supply water temperature at low mass flowrates to obtain a low energy usage of pumps (diminished pressure losses) and good quality of controlling.

Energy Benefits of Heat Pipe Technology for Achieving 100% Renewable Heating and Cooling for Fifth-Generation, Low-Temperature District Heating Systems

“…Such a system may replace conventional floor heating systems with exergy-demanding circulation pumps and makes it technically feasible to introduce radiant panel technology as a retrofit option also for old buildings without demanding additional pump power by using heat pipes. There is already some research in this subject matter, like Amanowics, L. has investigated how to control the heating capacity with the temperature and supply water of the district energy supply system [50]. He carried out experiments to find the relationship among operational variables and derived design correlations for typical applications.…”

An Experimental Study of a Thermally Activated Ceiling Containing Phase Change Material for Different Cooling Load Profiles

“…The structure of the test stand is depicted in Figure 1. A full description of the test stand and the experimental results of the phase change material are detailed in [42]. The 40-mm-high cooling ceiling consisted of two 0.6 × 1.2 m panels and one 0.6 × 2.4 m panel (Figure 2).…”

“…The phase change temperature range was adjusted to the operating temperature of the thermally activated ceiling without PCM filling to achieve as large as possible a temperature difference between the ceiling surface and the room air temperature during passive cooling, while providing thermal comfort and preventing condensation of water vapor from the air in the room. In the temperature range of 18-25 • C, a 5 cm layer has the same thermal capacity as a 16 cm reinforced concrete ceiling [42]. Partial enthalpy of PCM in modules is presented in Figure 4.…”

Peak Power of Heat Source for Domestic Hot Water Preparation (DHW) for Residential Estate in Poland as a Representative Case Study for the Climate of Central Europe

“…The most common system is floor heating, but in works [11,12], the innovative ceiling heating and cooling panels have been presented, showing the increase in their efficiency thanks to the use of an appropriately corrugated surface. An important role for the energy efficiency of HVAC systems is also played by controlling their efficiency, which was described in the example of wall heating systems with heat pipes in the article [13]. Renewable energy sources that are most often used to meet the energy needs of buildings are the energy of the sun, wind, ground and the use of the so-called waste heat (heat recovery, i.e., from exhaust air in ventilation).…”