True reversible in heating and cooling
Solutions for heating and cooling in heat pumps have been around for a long time. Usually, a condenser and an evaporator are used, consuming space and energy and many refrigerants. And when a reversible chiller is used, either the heating or the cooling mode is less efficient. Hypertwain is a revolutionary new technology that optimizes both cooling and heating and keeps the need for space, electricity and refrigerants to a bare minimum. Hypertwain is the answer to the rising demand for comfortable indoor climate – and the absolute necessity of using fewer resources.
Designed for efficient work
With Hypertwain, SWEP introduces a new heat exchanger that combines the SGHX with the evaporator into one. Getting all the benefits of the using a SGHX without the disadvantages. Unlike a normal brazed plate heat exchanger, the plate has a more purely dedicated area for the evaporation process and just a small area close to the outlet port that is optimized for superheating the refrigerant.
From a theoretical point of view, it is well known that co-current evaporation is the preferred operation mode. The higher temperature difference at the heat exchanger entry stimulates the evaporation more than it would with a counter-current flow resulting in advantages such as:
- Improved refrigerant distribution
- Improved freeze resistance
- Possibility to optimize both heating and cooling performance in the reversible system
The issue that arises with co-current flow is to achieve a proper and stable level of superheat. Since the primary and secondary side temperatures will approach each other quickly at the heat exchanger outlet, there is a risk for pinch point, which means that high performance and reasonable superheat cannot be reached.
Adding another heat exchanger to the suction line (suction gas heat exchanger, SGHX) removes the superheat from the evaporator. The suction gas heat exchanger generates the necessary superheat of the evaporated refrigerant by using the subcooled refrigerant in the liquid line. It enables the evaporator to operate efficiently with less risk of a pinch point as the SGHX generates the superheat. Adding an SGHX can increase footprint, cost and additional pressure drop. Hence it is not always an appreciated solution.
With Hypertwain, SWEP introduces an innovative heat exchanger that combines an SGHX and an evaporator. It gives you all the benefits of an SGHX but none of the disadvantages. Unlike a conventional brazed plate heat exchanger, the plate has a dedicated area purely for the evaporation process and just a small area close to the outlet port which is optimized for superheating the refrigerant. The small superheating area works as an integrated suction gas heat exchanger connected to the warmer refrigerant liquid line and it uses this liquid to superheat the evaporated refrigerant. With the SGHX integrated in the plate, there is no physical distinction between the SGHX and the evaporator part.
With this design, SWEP has found a way to use the plate more efficiently, only needing a few percent of the plate area to superheat the refrigerant gas. In a conventional evaporator, the area required for superheating the refrigerant can account for roughly 30 percent. This new plate optimization increases the part of the plate area dedicated for the evaporation process, which improves the evaporation temperature and, thereby, the system efficiency. As the superheat no longer is an issue, Hypertwain always operates as a co-current flow evaporator.
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