Hot Water Coils

Akvaterm make copper heat exchange coils for their tanks with rated flows from 35 l/min to 200 l/min. Coils are normally made from finned copper tube of 18mm, 22mm or 28mm diameter, but stainless steel coils can be made to order. All coils are 10 bar pressure rated.

Coils are used for the production of domestic hot water (DHW) and can be used to connect heating systems on hydraulically separate circuits. (Direct connection of heating systems is recommended where possible). Coils are also used for heat input from a solar thermal system or a heat pump system.

An AKVA or AKVASAN ‘EK’ model tank is supplied with one LK35 (35 l/min) coil of 22mm finned tube. An AKVANTTI ‘EK’ model tank is supplied with one LK45 (45 l/min) coil which is a longer version of the LK35. These coils are fitted in removable ‘hatches’. These tank models are made with either one or two coil hatches as standard but can be made to order with extra coil hatches.

AKVAir Solar and Solar Plus tanks are fitted with non-removable coils without hatches. The DHW coils are made in 22mm finned copper tube and the solar coils in 18mm finned copper tube. The standard Solar model is fitted with one solar and two DHW coils. The Solar Plus model has an extra solar coil (in the top of the tank).

For DHW application the cold supply pressure must be considered due to pressure drop through the coil(s). The stored thermal energy in the tank is better used if DHW is produced by two DHW coils in series – a pre-heat coil in the lower part of the tank and a secondary coil at the top. Pressure drop is approximately 0.5 bar per coil at the maximum rated flow of the coil.

Model	Heat Exchange Capacity (kW)	Diameter (mm)	Length (mm)	Coupling size (inches)	Flow (l/min)
LK 35	90	160	750	¾	35
LK 45	110	160	750	¾	45
LK 60	150	160	1,250	1	60
LK 80	205	250	900	1 ¼	80
LK 100	255	300	1,000	1 ½	100
LK 120	310	300	1,100	2	120
LK 140	365	300	1,100	2	140
LK 160	420	300	1,100	2	160