In Greece, the most common practice for producing domestic hot water (DHW) with a heat pump involves using a conventional DHW tank (boiler) with a single coil. While this method was effective during the era when oil boilers dominated, it is not the most efficient solution for heat pumps.

The Two Main Issues:

  1. Slower Heating Rates: Heat pumps heat water more slowly compared to oil boilers.
  2. Lower Operating Temperatures: Heat pumps operate at lower temperatures, which makes the small coils in traditional boilers inefficient for transferring heat effectively. This inefficiency delays the water heating process and increases strain on the heat pump.

Improved Options:

A better choice is using “heat pump boilers” equipped with larger coils, which provide more efficient heat transfer. However, even this solution limits the heat pump’s performance due to the limited surface area of the coil. As a result, the heat pump must operate longer, reducing energy efficiency and increasing waiting time for hot water.

The Optimal Solution:

The most efficient approach involves specialized hydronic tanks provided by heat pump manufacturers. These systems are specifically designed and tested to maximize the thermal power of the heat pump. They ensure faster water heating, reduced operating times, and minimal waiting for hot water, delivering maximum performance and comfort.

SPRSUN’s Advanced Hydronic Tank Solution:

SPRSUN offers a hydronic tank that not only accelerates water heating and enhances system efficiency but also integrates several essential components required for any heat pump installation. This eliminates common installation errors when these components are installed individually.

Key features of the SPRSUN hydronic tank include:

  • Stainless Steel DHW Tank: The DHW tank is made from stainless steel and is charged by the SPRSUN heat pump via a 15-meter-long stainless steel DN32 coil. Thanks to its large heat exchange surface, water heating is rapid and efficient.
  • Integrated Components: The system includes a negative pressure valve, pressure relief valve, drain valve, expansion tank, and a three-way valve for switching between heating and DHW.
  • Buffer Tank Integration: The tank also features a 60-liter buffer tank to ensure proper heat pump integration in homes with diverse heating and cooling zones. This supports network balancing and optimizes performance.

Backup and Versatility:

The hydronic tank is equipped with two standard 3kW electric heaters—one for the DHW tank and one for the buffer tank—for backup heating. These heaters operate automatically and are controlled by the heat pump’s touch controller.

Additional Features:

  • Dual-Zone Heating Control: Includes two sensors and an analog interface for a three-way mixing valve, allowing simultaneous supply to radiators and underfloor heating.
  • Solar Collector Functionality: Supports forced-circulation solar collectors with a sensor and power output for a solar pump.
  • DHW Recirculation Functionality: Ensures hot water is readily available at all taps.

Simplified Installation:

SPRSUN’s hydronic tank significantly reduces the installation time for the heat pump and DHW system. The connection requires only two water pipes and a communication cable since all the above features and components are pre-assembled within the hydronic tank and controlled directly via the SPRSUN touch controller.

By choosing SPRSUN’s hydronic tank, you can enjoy a highly efficient, reliable, and easy-to-install system for producing domestic hot water with a heat pump.

Antonis Paskalis, Mechanical Engineer MSc, AUTh, Technical Director at Thermovent Hellas S.A.