Ice slurry generation & heat pump case studies chosen for ATMOsphere Europe 2013

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The ATMOsphere Review Panel has selected additional case studies to be presented at ATMOsphere Europe 2013. Vacuum freezing ice slurry generation and decentral & central natural refrigerants heat pumps are the topics of discussion. The case studies will be presented during the Heat Pump Session and the Air-conditioning Session of ATMOsphere Europe 2013.

The following technology case studies have been selected for the upcoming ATMOsphere Europe 2013 and will be presented during the Heat Pump Session, which will take place on 15 October, and the Air-conditioning Session, which will take place on 16 October.

Energy efficient vacuum freezing ice slurry generation using a R718 compressor by Mathias Safarik, ILK Dresden

Ice slurry is a pumpable binary mixture of water and ice. It can be used as secondary refrigerant and phase change material for storage of cold. Within the vacuum freezing process ice slurry is generated by the evaporation of water at a temperature of 0 °C and a pressure as low as 6 mbar. The vapour is compressed by a centrifugal compressor and condensed at a higher temperature. Ice slurry is stored in a tank and pumped to external heat exchangers providing high cooling capacities. The effective evaporation temperature of the cooling cycle is 0 °C … -1 °C which is considerably higher than in conventional ice slurry generators or chillers charging block ice storages. Therefore the efficiency can be increased by about 30 %. The technology can also be adapted for heat pump applications using zero degree water as heat source. This presentation will focus on the compressor technology developed by ILK for low pressure water vapour and its application for the vacuum ice process. The technology allows ice generation (charging) capacities of 50 kW to 500 kW per module and almost unlimited discharging capacities. The design and results of a 50 kW demonstration plant installed in Dresden will be presented.

According to Mathias Safarik, Head of Department Applied Energy Engineering, ILK Dresden, the key features of this technology include: “Considerably higher efficiency compared to conventional block ice storage or scraped surface ice slurry generators, efficiency increases about 30%. No heat exchanger is needed in the storage tank. Ice storage can be charged over night when ambient temperatures are low. Therefore, the condensation temperatures of the chiller are low, increasing the efficiency of the cooling cycle. Compared to on-time generation of chilled water, the overall efficiency of the chilled water supply using vacuum ice storage can be higher. It uses a clean, cheap, abundant phase change material with a large enthalpy of melting (333.5 kJ/kg). It employs the natural refrigerant water (R718). The storage capacity is not linked to the ice generation capacity. High, short-duration cooling loads can easily be matched by using the ice/water mixture as a coolant/secondary refrigerant.”

Decentral and central heat pumps with or without HFCs? by Menno van der Hoff, KNVvK & NVKL

In recent years, many sectors have started to ban or banned CFC/H(C)FC in favour of natural refrigerants. The Energy Performance Building Directive and local regulations have increased building quality, leading to lower heating demands. However, the cooling demand continues to rise. End users do not want to compromise on indoor climate. Thus, local heating and mutual cooling demands are becoming a frequent fact. This doesn't decrease our CO2 footprint emission enough. Heat pumps are great machines providing both efficient heating and cooling. But globally, this sector greatly relies on HFC gas. The presentation highlights the large VRF sector. For the future, these gases are banned, but F-Gas policy requires new solutions too.

“To solve this, we have to separate the small / decentral heat pumps from the large and central heat pumps. Some basic HVAC systems are explained. Often, low GWP and natural refrigerant solutions are already available, are presented or are under development. Systems can be made with direct expansion or indirect with water loops. Adding thermal energy storage is a superb feature in moderate climates, to operate in a passive manner. A decentral propylene system and a central propane HP system are shown as examples,” says Menno van der Hoff, Product Manager HVAC at Colt International.

Environment-friendly heating with R290 heat pumps by Dr. Joachim Maul, ait-deutschland

In recent time, R290 has again become an appropriate refrigerant for heat pumps. Due to the fact that temperatures of 70°C can be reached, heat pumps with propane are a good technology for the renovation market to substitute gas or oil boilers. Since a new generation of heat pumps with R290 was introduced in the market a few years ago, an overview of that refrigerant from the view of a manufacturer will be given. The presentation also includes application experience and consideration of efficiency.

Green HP – development of next generation components and heat pumps with natural refrigerants for retrofitting building in Europe by Thore Oltersdorf, Fraunhofer

In 2011 a FP7 call for ‘Next Generation Heat Pump’ was invoked. This R&D topic is aimed at the development of very efficient heat pumps using alternative refrigerants (e.g. natural refrigerants), and high power heat pumps. Out of this call, two projects were accepted. The presentation will cover the introduction to one of these European projects called GreenHP ( and its current activities.

“The remarkable feature of this project is related to the focus only on the cooperation and pre-product development at the level of heat pump component suppliers (4 out of 7 partners). This feature promises highest impact for heat pumps in Europe during and after the project since there are no exclusive results for a single final device manufacturer. But it needs a clear strategy to link activities and results close to manufacturer's need,” says Thore Oltersdorf, Head for heat pump development within the Group “Heat Pumps” at Fraunhofer.

About ATMOsphere Europe 2013
15 & 16 October at the Crowne Plaza Le Palace Hotel in Brussels, Belgium

For the fifth consecutive year, ATMOsphere Europe 2013 serves as the meeting point to discuss the latest developments concerning natural refrigerants. In addition to several technology case study presentations, the conference features leading end users and consumer brands and suppliers, who will discuss their experiences with natural refrigerants. Key policy representatives will provide an in depth look at the upcoming F-Gas regulations with input from Members of the European Parliament and national governments.

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