DHW Series

Indirect Coil Heat Exchanger Tanks Stainless Hydronic Tanks For Domestic Water Heating

Solar water heating tanks or other indirect tanks with coil heat exchangers can be used for domestic water heating with Chiltrix air-to-water heat pumps if they have a proper design. Chiltrix offers totally unique ultra-high-performance stainless indirect tanks designed specifically for air-to-water heat pumps, the DHW105 and the DHW80 which can be included in official US DOE water heating packages. The DHW40 is available as a stand-alone indirect tank that may be used with the smaller sized Chiltrix heat pumps, however, it is not part of an official water heating package at this time.

Another World Record Set by Chiltrix

Chiltrix now has officially set ANOTHER WORLD RECORD. In addition to our heat pumps which hold various world records for space heating/cooling efficiency, Chiltrix has set several new world records for water heating, starting with a tank that has achieved an unprecedented UEF 4.95 (highest efficiency rating among all residential water heaters) with First-Hour Ratings up to 133 Gallons (highest among all residential water heaters under 119 gallons). Energy Guide values are U.S. Dept. of Energy Certified.

Between 2-5x More Efficient than Electric Water Heating

An extra feature of the Chiltrix reverse cycle chiller (also known as an air-to-water heat pump or hydronic heat pump) is domestic hot water heating. A special 3-way valve allows the Chiltrix unit to automatically provide high-efficiency water heating by taking a brief pause from its current duties of space heating or cooling, quickly bringing the DHW (Domestic Hot Water) tank back to the target temperature, and then resume its former task of space heating or cooling.

This feature leverages the high COP of the heat pump unit to provide water heating that is 2 to 5 times as efficient as electric water heating, delivering up to 70% energy savings compared to an electric water heater. This means you can get up to 70% of your annual water heating for free.

Note that a standard electric water heater has a coefficient of performance (COP) of 1.0, meaning it is 100% efficient — one kW of electrical input gives one kW of heat output. 100% efficiency sounds good, but not really. Depending on ambient temperature, a heat pump such as Chiltrix will have a COP of between 2 and >4 (200% to >400% efficient) and up to COP 6, depending on ambient temperature. That’s why heat pump water heaters are becoming popular.

Adopting the European approach to heat pump system design, the Chiltrix DHW multi-function method allows your heating/cooling system to also perform as a high-efficiency water heater. And the Chiltrix method has higher net efficiency than a typical USA-style self-contained heat pump water heater because the “cooling” side of the Chiltrix water heating system is outdoors and does not rob heat from the indoors during winter. The water heating function can be used with Chiltrix in a ducted design, with fan coils, with radiant heating, air handlers, or with any combination of the above. Further below is a diagram of a system’s major components, fan coil system with water heating.

Highest Corrosion Resistance

The Chiltrix line of 2205 Duplex stainless tanks offers the highest corrosion resistance of any available stainless steel tank material. 2205 duplex stainless steel is a true engineering marvel, boasting roughly double the yield strength of standard 316L and superior resistance to corrosion and stress-cracking, making it the ultimate, high-performance choice for demanding, chloride-rich or potable water environments. 2205 has a PREN of roughly 35, while 304 is around 18–20. This represents an 80–95% increase in its ability to resist localized pitting and crevice corrosion.

Recirculating Systems:

Note #1Neither the Chiltrix heat pumps nor domestic hot water tanks are specifically designed for recirculating hot water systems, however we do offer proven recirculating system designs, see our DHW with recirculating system document here.
Note #2If you select an indirect tank from a different supplier that’s fine, just make sure it has a coil with a minimum of .375 ft^2 of coil surface area per gallon, with at least 1″ ID, and can be configured with a backup element. Chiltrix tanks have a coil surface area of 0.48 to 0.98 ft² per gallon for fast recovery and high performance

Compare Chiltrix Heat Pump Water Heating to All Certified Heat Pump Water Heaters (All electric powered heaters) U.S. Department of Energy Compliance Certification Database

Super-Efficient Heat Exchanger Tanks (Ultra-High Performance All-Stainless Steel Tanks)

Produced by Chiltrix for maximum performance with a heat pump, these tanks have a giant, oversized, convoluted coil. Inner tanks use 2205 Duplex stainless steel for maximum corrosion resistance, outer tank is SUS 304 stainless steel.

Note: In California you cannot order the package model numbers below but you can achieve the same result by ordering the heat pump and tank separately. Due to CA regulations they need to be ordered as separate items (same price either way).

71 Gallons Net

• DHW80 All-Stainless Heat Exchanger Tank, 66 Ft. * 1.25″ convoluted coil
  Spec Sheet
• First-Hour rating 88 gallons / UEF 3.31 when used with CX50DHW80NR Package
• First-Hour rating 87 gallons / UEF 3.49 when used with CX35DHW80NR Package

99 Gallons Net

• DHW105 All-Stainless Heat Exchanger Tank, 196 Ft. * 1.25″ convoluted coil
  Spec Sheet
• Reverse First-Hour rating 133 gallons / UEF 4.95 when used with CX50 / Package: Hitzewelle CX50DHW105RIDNR
• Reverse First-Hour rating 101 gallons / UEF 4.95 when used with CX35 / Package: Hitzewelle CX35DHW105RIDNR
• Standard First-Hour rating 80 gallons / UEF 3.75 when used with CX35 / Package: Hitzewelle CX35DHW105NR
• Standard First-Hour rating 93 gallons / UEF 3.69 when used with CX50 / Package: Hitzewelle CX50DHW105NR

The Chiltrix DHW80 tanks (71 gallons net of coil) and DHW40 (36 gallons net of coil) are designed to outperform every indirect heat exchanger tank or solar tank on the market, with .43 ft^2 per gallon of coil surface area, the fastest heat transfer, and truly exceptional durability. The DHW 40/80/105 tanks convoluted coils disrupt laminar flow for a further increase in thermal performance. The DHW105 tanks have a convoluted coil with an unprecedented 98 ft^2 of coil face per gallon.