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Phase change material slurries and their commercial applications (PAMELA)

Risultati finali

The industrial cost of PCMS are not yet fully established, it is however estimated to be in the region of 2 Euros per kg. The required inhibitors are also estimated to cost around 2 Euros per kg, with only a small amount required per installation. Traditional heat transfer fluids used for the technologies envisaged are water/glycol mixes. There may be the need to add glycol to the slurries where temperature cycles drop below 5ºC thereby adding to the cost. However, the potential energy savings by reducing pumping power by 64% will more than compensate for the higher initial material costs. For example a user paying 0.10 Euros for each unit of electricity could realise savings of 61 Euros per year per pump. This does not take into account the cost of purchase, which is dependent upon the capacity of the system.
The potential energy savings established in WP4 indicate significant potential reductions in energy use for air-conditioning systems. The reduced electrical energy requirement should allow suppliers to better meet demand requirements from sustainable resources, without recourse to quick-response fossil-fuel based energy sources. To use the slurries instead of water-based heat transfer fluids will lead to a drop in required pumping power by over 50%. Production of 1kWh of electricity produces 0.43kg of carbon dioxide, (UK National Energy Foundation), a switch to slurries could save, for such pumps for continuous operation on an annual basis, 264kg of CO2 per pump.
Small scale heat exchangers and storage systems for the developed PCM slurries possessing small temperature and pressure losses in the heat exchangers, high heat transfer rate and if appropriate thermal stratification in the storage system will be designed. The systems will be generic to a range of technologies, optimisation of design will be undertaken with regard to specific heat exchanger/storage unit charging/discharging patterns for solar thermal applications, burners operating at a lower heating capacity than their modulation range and peak load operations. This will involve improving the rate of heat transfer, temperature loss and stratification in the storage. Component simulation models will be developed and validated by the experimentation. So far a storage test stand with an internal heat exchanger has been built up and measurements with a microencapsulated slurry with a phase change at 65 °C have been undertaken. Heat capacities, heat transfer rates and segregation of solid particles in the storage have been analysed. A simple 1-dimensional simulation model for a storage tank incorporating PCM slurries has been built up; considerations about a 2-dimensional model are in progress. A model for a counter flow heat exchanger with a slurry flow on one or both sides has been built up.
A wide scope approach has been made to delimit categories of barriers that could impede the market penetration of Phase Change Material Slurries in general. The investigation of optimal market penetration paths for specific PCMS applications calls for reliable market studies, which focus on narrower domains of the PCMS technology. General marketability issues that need to be considered for the PCMS technology at large can be categorised into the following five groups: - Information; - Risk; - Environmental; - Financial; - Market characteristics. This list of categories and the issues addressed in each category are surely not exhaustive (e.g. could include policies and regulations) but contain the most relevant domains of assessment for today’s markets. Naturally, PCMS technologies will be compared to technically alternatives and competitive conventional technologies with regard to costs, functionality, availability, technical support and increasingly also to environmental compatibility. The rapid change and interdependence of today’s markets intensifies the decision-maker’s need for up-to-date trustworthy and comprehensible information. The choice of investors will undoubtedly depend strongly on the efforts put in communicating the distinguishment of a PCMS application from an alternative conventional application. Misperceptions of technical and economic risks involved in the application of PCMS systems may be avoided by conducting reliable empirical studies on full scale demonstration systems, monitored by independent syndicates to promote transparency and credibility. Since initial investment involved in implementing PCMS applications at this stage of development might constitute a disadvantage compared to conventional technologies an influential step towards commercialisation will demand solutions for yielding attractive payback times for PCMS applications. Ideally, commercialisation of PCMS applications should be integrated in the well-established marketing and distribution channels for conventional thermal energy management equipment. In order to exploit the potential markets of strongly populated regions which have beneficial climates for space conditioning PCMS applications, but whose economies and industries are relatively weak, the costs and concepts of the concerned PCMS applications need to be adapted for such regions. This might only be accomplished with specific multilateral commercial agreements between the stakeholders.
Different PCMS has been tested in the DSC for a range of applications. This includes a 6°C emulsion and a 27°C and 65°C encapsulated parafin. A testing site for the slurries in real size systems has been set up and 2 different slurries has been tested with 5 different pumps for there stability and usability in various applications. A simulation model for PCMS has been implemented in the simulation environment ColSim and is no validated with the measured data from measurements. With this model, parameter studies can be carried out to determine useful material parameters and promising applications.
The ability of companies to create jobs using these materials is low. It is expected that there will be neither a loss or great expansion in jobs as a result of the adoption and wide-spread use of the slurries, more manufacturing will be able to maintain current jobs and revenue in the face of competition from the USA and Japan.
A detailed report outlining the charging and discharging of energy to and from a PCM slurry was prepared. A wide variety of applications are covered and span results from the small scale analytical chemistry results from DSC and TG experiments to the large scale results from test rigs.
A review of literature and patents in the fields of ice slurries, phase change materials and PCM slurries. A publishable literature review incorporating the following chapters: Principles of PCM Slurry Technology - Energy Storage; - Energy Transportation. PCM Slurry Applications - Cooling Food; - Solar Energy; - Air Conditioning. PCM Slurries - Principles and Forms of Encapsulation - Materials Applicable as Slurries - Methods for Structuring of PCM Fluids; -- Ice Slurry Modification; -- Micro-encapsulation ; -- Emulsification ; -- Shape-stabilization; -- Cross-linkage. Technologies and Commercialisation of PCM slurry - Ice slurry; - Paraffin Slurry; - Clathrate Slurry. Patents on PCM Slurry Applications - Ice slurry; - Paraffin slurry; - Clathrate slurry.