Types of chillers

LiBr (lithium bromide) chillers are used to generate low temperatures by means of heat. The electricity consumption is usually less than 0.5% of the cooling capacity.

Single-stage chiller

This type of chiller is mostly used with driving temperatures from about 80°C and allows cooling for air conditioning using heat sources such as district heating or solar collectors.

If the driving energy has a low temperature, such as district heating with summer temperatures of flow = 70°C, return = 55°C, the use of a special-purpose chiller should be considered.

Technical data (guideline values)

Driving temperature
(generator)

Flow: 70–100°C
Return: approx. 10 K lower

Medium temperature
(absorber + condenser)

Return: max. 35°C
Flow: approx. 10 K lower

Low temperature
(evaporator)

Return: 6–8°C
Flow: 5–10 K higher

COP
(COP = Q useful / Q input)


approx. 0.7

Driving temperature
(generator)
Flow: 70–100°C
Return: approx. 10 K lower

Medium temperature
(absorber + condenser)
Return: max. 35°C
Flow: approx. 10 K lower

Low temperature
(evaporator)
Return: 6–8°C
Flow: 5–10 K higher

COP
(COP = Q useful / Q input)
approx. 0.7

Single-stage chiller

Double-stage chiller

The advantage of this chiller type is that twice the cooling capacity and thus twice the COP can be achieved with the same driving power. A driving temperature of at least 140°C is required in this case.

Historically, this was the most commonly used type of chiller when there was no electricity available for cooling.

Technical data (guideline values)

Driving temperature
(generator)

Flow: 140–170°C
Return: 10–15 K lower

Medium temperature
(absorber + condenser)

Return: max. 35°C
Flow: approx. 10 K lower

Low temperature
(evaporator)

Return: 6–8°C
Flow: 5–10 K higher

COP
(COP = Q useful / Q input)


approx. 1.4

Driving temperature
(generator)
Flow: 140–170°C
Return: 10–15 K lower

Medium temperature
(absorber + condenser)
Return: max. 35°C
Flow: approx. 10 K lower

Low temperature
(evaporator)
Return: 6–8°C
Flow: 5–10 K higher

COP
(COP = Q useful / Q input)
approx. 1.4

Double-stage chiller

Chiller for low driving temperature

This chiller type is designed for very low temperatures on the driving energy side. They are used, for example, to allow the heat from district heating to be used as the driving energy source despite low network temperatures in summer.

Specification (example)

Driving temperature
(generator)

Flow: 75°C
Return: 55°C

Medium temperature
(absorber + condenser)

Return: 33°C
Flow: 28°C

Low temperature
(evaporator)

Return: 14°C
Flow: 7°C

COP
(COP = Q useful / Q input)


approx. 0.55

Driving temperature
(generator)
Flow: 75°C
Return: 55°C

Medium temperature
(absorber + condenser)
Return: 33°C
Flow: 28°C

Low temperature
(evaporator)
Return: 14°C
Flow: 7°C

COP
(COP = Q useful / Q input)
approx. 0.55