Heat Storage Tank and Photovoltaics

A heat storage tank and photovoltaics are an ideal combination that allows for the efficient use of solar energy to heat the home and prepare hot domestic water. The heat storage tank, an energy storage unit, enables the storage of thermal energy produced by photovoltaic panels by converting electrical energy into thermal energy.


Heat Storage Tank – why is it so necessary in a photovoltaic installation?

The NOEL heat storage tank is an ideal solution for owners of photovoltaic installations who want to fully utilize the energy produced by their solar panels. Thanks to the heat storage tank, it is possible to store energy generated during peak production times, especially in the spring and summer months when the days are longer and sunnier.

In areas saturated with photovoltaic installations, disconnections can occur due to too high voltage in the network. Inverters increase the voltage to send energy to the grid, but if many installations feed energy at the same time, the voltage may exceed the threshold of 253 V, causing inverters to reset and photovoltaic efficiency to drop.

To avoid shutdowns, it is worthwhile to use excess energy to heat the heat storage tank, which acts as an energy storage unit. The water heated in this way can be used for preparing hot domestic water and for supporting home heating, especially in the spring when energy production is already high but days are still cool.

Using a heat storage tank in conjunction with a photovoltaic installation offers many benefits, such as increased profits from photovoltaics, avoidance of problems related to disconnections, and acceleration of the return on investment.

Heat pump connection diagram with solar panels and MPPT module

In-Grid – heating the buffer tank with photovoltaics during surplus electricity production.

f you’re the owner of a photovoltaic installation and are looking for ways to reduce electricity costs, then the Smart Heat Storage could be your best ally. This is particularly important for prosumers who want to join the ranks of solar power plant owners after April 1, 2022, as changes in the billing method introduced at that time mean that energy produced during the day is no longer stored by the utility company without cost.

Therefore, the thermal energy storage is an ideal solution for those who want to reduce the flow of energy between the grid and the photovoltaic installation. As a result, part of the produced energy is used for immediate needs and for heating the buffer tank, and only the excess is sent to the grid. This way, you use your own produced energy for heating domestic hot water and for heating in the spring days.

Stored energy is used when energy production is lower than its demand, e.g., in the evening or in less efficient production periods. When demand exceeds production, energy is drawn from the grid. Such operation means the energy grid is used only to a necessary minimum, which is an excellent example of energy autoconsumption.

What are the benefits of heating the buffer tank with the In-Grid principle?

  • increasing profit from photovoltaic installations – unlike situations where excess energy is fed into the network, using the buffer allows for the on-site consumption of energy. This accelerates the return on investment.
  • protecting inverters from frequent restarting – another benefit is limiting the problem of disconnection caused by too high voltage in the network. Disconnecting inverters related to this issue negatively affects their lifespan and can significantly worsen production results.
  • stable energy production – thanks to the use of a heat buffer tank, surplus energy can be stored and used for heating domestic water or to support the heating system during periods of lower energy production. As a result, frequent disconnections of the installation are avoided, contributing to stable energy production.

Off-Grid – heating the buffer tank with photovoltaic panels using the MPPT function – as an independent heating source.

Do you want to use solar energy for heating domestic water without the need to connect your photovoltaic installation to the grid? In that case, we have the perfect solution for you – combining photovoltaic panels with efficient resistive heaters installed in a heat storage tank with a copper coil for domestic hot water (DHW). NOEL offers ready-to-use solutions of this class, where the entire installation utilizes an MPPT (Maximum Power Point Tracking) controller appropriately selected for the heaters.

The MPPT controller works by adjusting the output voltage to ensure that the solar panel operates at maximum efficiency. Thus, when atmospheric conditions change (e.g., when clouds cover the sun), the controller automatically adjusts its parameters to always extract the maximum amount of energy from the photovoltaic panels and use it to heat the buffer. This combination provides the opportunity to use solar energy for heating domestic water independently and autonomously.

Benefits of Off-Grid connection of photovoltaics with NOEL buffer tanks:

  • savings – free domestic hot water from April to September
  • independence – complete independence from both the public energy infrastructure and electricity prices
  • no service required – the installation does not require annual services, it is very durable, allowing for many years of use