[01] Christopher Ian Wright, Research and Development Department, Global Group of Companies, Cold Meece Estate, Cold Meece, Staffordshire, United Kingdom. [02] Eole Picot, RAMS Department, Alte Technologies SLU, Lliça de Vall, Barcelona, Spain.

Background: The heat transfer fluid (HTF) most commonly used in concentrated solar power (CSP) plants is eutectic mixtures of biphenyl and diphenyl oxide (BDO) such as Globaltherm^ Omnitech, which can be used up to 400 degrees Celsius. Routine sampling and chemical analysis of solar HTFs plays a critical role in maximizing the profitability of CSP plants. Objectives: The current article outlines the sampling and chemical analysis of solar HTFs containing a eutectic BDO mixture and how to safety handle and store BDO HTFs. Methods: The Company’s database was searched to identify risk and method statements detailing the safe sampling of BDO HTFs and to identify the parameters to measure. Likewise, the safety datasheets for the company’s BDO HTFs were searched and used to outline how this type of HTF should be handled and stored. Results: Like any HTF, the sampling of a BDO HTF needs to be conducted in a standardised manner to ensure it is done safely. The chemical testing of a HTF should include assessments of both ‘light’ and ‘heavy-ends’ (i.e., short and long-chain hydrocarbons); oxidative state; and, the potential flammability risk posed by light-ends. Other assessments include kinematic viscosity, contamination and component wear particles. In terms of safety, it is recommended that engineers are proficient with the safety data sheet for a BDO HTF to ensure they are sampled, handled and stored safely. General safety advice included: not allowing clothing soaked with a HTF to come into contact with or remain in contact with the skin; avoiding all personal contact with the HTF, including inhalation; wearing protective clothing; being vigilant that the decomposition of BDO HTFs may be flammable and hazardous to human health; and, knowing that personal protective equipment should be worn when sampling and handling a BDO HTF. Conclusions: Routine sampling of HTFs should be done whilst the HTF is live and conducted by a trained engineer that knows how to safely take a live sample as well as how to safely manage a BDO HTF. This includes being proficient in first aid should the BDO HTF come into contact with the skin, be ingested or inhaled. Lastly, BDO HTF condition should be tested on a regular basis and it is also advised to have this done by a company that specialises in this sector such as Global Heat Transfer, which has over 25 years of experience in this area of thermodynamics.

Heat Transfer Fluid, Heat Transfer Fluid System, Sampling and Chemical Analysis, Concentrated Solar Power, Eutectic Mixtures of Biphenyl and Diphenyl Oxide

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