The fluid in solar collectors, from which energy is extracted by the heat exchanger - is glycol
Solar Water Heater Systems - so solar collectors are typically not filled with water because in our climate, there is a risk of freezing and damaging the collector during winter. Therefore, they are filled with glycol, a non-freezing fluid. However, this is not pure glycol because pure glycol transfers heat rather poorly. It's actually a solution of glycol and water, with glycol making up about 30-50% of the mixture (typically, concentrations of 30-35% are used in solar collectors, while values around 50% are used in places like Scandinavia). The hot glycol from the solar collectors, once heated by the sun, is directed to the solar heat exchanger with the help of a circulation pump.
In the plate heat exchanger for solar panels, water flows through the second channel, the same water that is in the domestic hot water tank. Both fluids meet in the heat exchanger, but they are separated by thin steel plates. This prevents them from mixing, but allows the hot glycol to transfer heat to the water. This way water is heated practically for free, utilizing solar energy. It's essentially free heating, aside from the initial investment costs, of course.
Heat exchanger for solar panels - which model to choose?
First and foremost - it should be emphasized that the choice of a heat exchanger for solar panels must be made correctly. This means that if the solar heat exchanger is too small, the entire system will not function properly. An indication of an undersized heat exchanger might also be a situation where the system works relatively well during the summer, but the benefits of utilizing solar energy are almost invisible in the autumn.
It is natural that solar panels - or speaking more professionally, solar panels - produce significantly less energy during the autumn-winter period than in summer. However, when the heat exchanger for solar panels is properly selected, we can expect significant support for the heating system, especially on sunny winter days. This applies even during periods when the days are shorter than in summer. The correct selection of a plate heat exchanger for solar collectors determines whether the system realistically heats water only in summer or throughout the year.
Before purchasing a heat exchanger, it is also worthwhile to discuss with a plumber the size of the connections. In most cases, in detached-family homes, a heat exchanger with 3/4" connections is sufficient, but this is not a rigid rule. In some cases especially when you have a larger domestic hot water tank, a heat exchanger with 1" connections may be needed.
Heat exchanger for solar heating - supporting central heating
This aspect should be absolutely taken into account because a solar heating - solar panels on the roof - does not have to serve solely for heating domestic hot water. With the proper configuration of the central heating system, it is possible to use solar energy from the collectors to heat domestic hot water in the summer and support central heating - for example, underfloor heating - in the winter.
To achieve this, it is necessary to properly design the heating system, in which mixing valves or additional circuits can be used, which can be activated when needed. The central heating system can be connected to the glycol circuit of the panels using a heat exchanger - installing it, for example, on the bypass and limiting it with valves - so that in the summer it transfers all the energy only to DHW. The possibilities are truly diverse.
Many people underestimate the thermal gains that can be achieved through collectors in the winter. It turns out that they can be - unexpectedly - quite satisfying. It is definitely worth investing in a heat exchanger and considering recovering this energy, especially if you have glycol solar panels on the roof. Especially if you have a few more solar panels.
Glycol heat exchanger - from Nordic Tec
The plate heat exchangers for solar panels that we have placed in this category are glycol heat exchangers. We guarantee their proper operation with this medium, practically regardless of the glycol concentration in the water (as we mentioned, the use of pure glycol is not necessarily needed and not always recommended).
The question regarding the ability to work with glycol in the case of Nordic Tec plate heat exchangers is one of the most common questions about heat exchangers. This question arises so frequently not only due to the use of glycol in solar systems but also increasingly to protect heat pump circuits from freezing using a glycol heat exchanger (water glycol heat exchanger for heat pump).
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Besides using heat exchangers to separate heating systems utilizing solar energy, they can also be utilized for various other purposes. Take a look at the following categories as well:
We also invite you to take advantage of technical assistance in selecting a heat exchanger - whether it's for solar panels or for any other purpose.
Feel free to contact us for assistance.
