Common questions
HDC-300 frequently asked questions
What is a dual coil hot water tank?
A dual coil hot water tank is a cylinder fitted with two independent heat exchanger coils, allowing two separate heat sources to transfer energy to the stored water simultaneously or independently. Heatlyt's HDC-300 uses an upper 3.2 m² coil (for the primary heat source, typically a heat pump) and a lower 1.3 m² coil (for a secondary source such as solar thermal), with both circuits isolated from the potable water stored in the SUS304 tank body.
Can the HDC-300 connect to both a heat pump and solar panels at the same time?
Yes. The HDC-300's dual coil configuration allows simultaneous connection to a heat pump via the upper 3.2 m² SUS316 coil and a solar thermal collector array via the lower 1.3 m² SUS316 coil. Each circuit operates independently with its own flow and return connections, so both heat sources contribute to the stored water temperature without cross-contamination of the heating circuits. This makes the HDC-300 the preferred choice for dual-source renewable energy systems.
What is the coil surface area of the HDC-300?
The HDC-300 has a total coil surface area of 4.5 m², comprising an upper SUS316 coil of 3.2 m² and a lower SUS316 coil of 1.3 m². Larger coil surface area means faster heat transfer from the heat pump or solar circuit to the stored water, reducing recovery time. This combined 4.5 m² total is 30–40% larger than typical single-coil 300L cylinders, giving Heatlyt's HDC-300 a measurably faster heat-up characteristic.
