Thermal characteristics

What is the thermal performance of the DualSun SPRING panel?
As with all thermal solar panels, the power of our DualSun SPRING panels varies according to the temperature of the water in the panel.  At low temper...
What is the difference between the non-insulated and insulated versions of the SPRING panels?
We have three versions of our panel in our catalog: SPRING3 and SPRING4 non insulated SPRING3 and SPRING4 insulated SPRING4 finned   The non-insulated...
What is the stagnation temperature of the DualSun SPRING panel?
It differs slightly depending on the model: Model Stagnation temperature SPRING4 Finned 70°C SPRING4 Insulated 80°C SPRING4 non-insulated 70°C SPRING3...
What is the water temperature at the outlet of a DualSun SPRING panel?
The temperature at the outlet of our DualSun SPRING panels depends on several conditions: Solar irradiation (denoted as G, in Watt/m²) Outdoor air tem...
What is the minimum operating temperature of the SPRING panel?
The minimum operating temperature of the SPRING panels is -40 ° C.  Dualsun has passed the IEC 61215 standard which includes thermal cycling from -40°...
What are the thermal performances of the polymeric heat exchanger of DualSun SPRING panel ?
We often think that polymeric materials are not adapted for efficient heat transfer: everything is relative. We must keep in mind that the photovoltai...
How to explain the evolution of thermal coefficients of SPRING panels?
The SPRING 425 is the result of a continuous improvement process that has allowed a steady increase in thermal and electrical performance. Since we ...
What is the impact of water consumption on the thermal output of Dualsun SPRING panels?
In a solar water heating system, the Dualsun SPRING panel discharges the heat from the panel into the tank to which it is hydraulically connected. ...
Why does the non-insulated DualSun SPRING3 panel perform better at low temperatures?
The thermal power of a solar panel is calculated with the following formula: P = a0.A.G - a1.A.∆T(water-air) [Wth]  a0 = Panel optical efficiency a1 =...
How does the thermal power output of the SPRING panel change according to outdoor conditions?
As with all thermal solar panels, the thermal power of our DualSun panels varies according to several parameters. To analyze in more detail the parame...
How does the temperature gradient of the SPRING panel change according to outdoor conditions?
As with all thermal solar panels, the thermal behavior of our DualSun SPRING panels varies according to several parameters. In order to analyse in mor...
What does “gross area” mean in the SOLAR KEYMARK certification?
The words “gross area” from SOLAR KEYMARK is referring to the entire area of the solar panel. Until 2016, the reference for SOLAR KEYMARK certificatio...
How to read the thermal power curve on the DualSun Spring panel data sheet?
The thermal power curve provided in the DualSun Spring hybrid solar panel data sheet represents the "peak" thermal power depending on the application....
What is the performance difference between portrait and landscape panels installation?
None, The thermal efficiency is even whatever the disposition of the panel for the thermal part as for the photovoltaic. What Differs between the two ...
Are Dualsun SPRING panels recommended for heating water from an indoor swimming pool?
It is not recommended to install Dualsun SPRING panels for indoor swimming pools of individual homes. However, for indoor collective/municipal swimmi...
Can DualSun SPRING panels work with the thermosiphons effect ?
As with conventional thermal solar panels, a thermosiphon effect can be observed with DualSun SPRING panels when they are connected to a thermosipho...
Can Dualsun SPRING panels be used in District Heating Networks ?
Yes , Dualsun SPRING panels can be used to supply district heating networks (RCU). For that : they must be coupled with glycol/water heat pumps. the s...
Why is the rated thermal power of the wave panel calculated by the SPF so low?
The DualSun Wave panel is included in the list of solar collectors approved by the SPF; this guarantees the quality of the product. However in order t...
Is there a risk of thermal shock if cold water is injected into the hot panels?
No, there is no risk of thermal shock. During the SolarKeymark thermal certification, the modules are tested according to the ISO9806 standard. One of...
What is the link between the normative power output Wth/m² and the a0 coefficient (optical efficiency)?
The thermal power output (Wth/m2) listed on the front page of the technical data sheet is a normative value calculated from the η0 coefficient determi...
How to calculate the heat input of SPRING panels?
The caloric contribution of the DualSun SPRING panels on a solar tank or swimming pool is calculated using the formula for the amount of heat . The ...
Is there a risk of clogging with DualSun Spring panels over time due to the air permeability of the heat exchanger?
No. Clogging occurs by metallic corrosion. Since the exchanger and the DualSun links are made of polymer, they will not be affected, but other element...
What is the difference in thermal power between the Wave and the Spring?
The thermal outputs of the hybrid PV/T panels can be compared using the coefficients a0 and a1 which are given on the data sheets. The graphs below sh...
What is the stagnation temperature of the Wave panel?
The stagnation temperature of the DualSun Wave panel is 74.7°C . This was measured during TÜV certification tests in accordance with ISO 9806 (ex EN ...
What is the thermal performance of the DualSun Wave panel?
As with all solar thermal panels, the power output of our panels varies depending on the temperature of the water in the panel. The graph below shows ...
How is the difference in thermal expansion managed between the glass and the heat exchanger on the Wave panel?
The material of the heat exchanger is a grade of ferritic stainless steel whose coefficient of thermal expansion is very close to that of glass. Over ...