Roberto R. Aguiló, owner and principal engineer of Estudio Aguiló & Asoc. has worked in the Refrigeration Industry for 37 years leading more than 700 projects of supermarkets and other industrial applications. Actually, is President of AAF (Asociación Argentina del Frio) for the tenth time (since 1994 until today) and Past President of FAIAR (Federation of Iberoamerican Societies of Air –Conditioning and Refrigeration) and he was the first President of Argentina ASHRAE Chapter in 2005 and first President of ASHRAE Paraguay Chapter in 2017. He has served ASHRAE in a variety of positions including Student Branch Advisor, Chapter President, Region XII ARC, several Society Committees (International, Handbook, Refrigeration, Research Administration, Nominating, Developing Economies and Publication) He also has served in Publications and Educational Council, Technological Council, Member Council and in the Board of Directors as Society Director-at-Large. He is an ASHRAE Fellow and the recipient of the Distinguished Service Award, the Regional Award of Merit, John James International Activities Awards and Exceptional Service Award.
He received his degree in Industrial Engineering from Buenos Aires University in 1981 and is a registered professional engineer in Argentina (CPII). He has been President of Cotein S.A. and has worked in design and maintenance in other companies previously. In the field of Engineering Education, he was Professor of Refrigeration Installations at Universidad Nacional de Luján since 2002 till 2018. He has been Visitor Professor at other Universities of Argentina (Universidad Nacional de Misiones, UCES, UNLu) and he has dictated numerous courses in Private Institutes and Companies. He has published 2 books and numerous articles and papers in Argentina on topics related to refrigeration.
Mr. Aguiló is a member of the Asociación Argentina del Frio (AAF), the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and in the Consejo Profesional de Ingeniería Industrial.
Refrigeration is a method very used in food processing for economical and practical issues. The preserving of foods is done by two ways: chilling foods or freezing foods. In a chilling process it is needed to extract heat over freezing point (sensible). It implies that systems are relatively simple, and it could be done by a continuous process or a batch process that implies differences in refrigeration technology. In a freezing process it is needed to extract heat over and below freezing point (sensible and latent). It implies that systems could be much more elaborated, and (as same as the previous case) it could be done by a continuous process or a batch process. The same type of process could demand different amounts of energy depending mostly in the refrigerant selected and the technology used. The present paper covers the different ways and its efficiency of refrigeration processes.
Supermarkets are very important users of refrigeration systems and this type of construction has a big impact in the environment. It has different ways of impact on the environment (emissions of gases, liquids and solids) but considering refrigeration is the main user of energy in a supermarket, we have to take special care on this point, and the design and selection of the equipment will impact in the efficiency of the overall system.
Technology has changed a lot in the last years and the present paper covers the alternatives in the design project of a supermarket refrigeration systems and the way to improve its efficiency and to reduce refrigerants emissions to protect the environment.
There are different methods of control the refrigerant flow in an evaporator. Each one has its own advantages and disadvantages and the selection depends of the proposed use. The economy of the system is related to different way we use, but a technical consideration has to be done specially with the size of the systems for its impact in the first cost.
The present paper covers the different types of flow controls methods, its energy analysis and the equipment we have to use in each occasion, specially in the design of liquid overfeed systems.
Carbon dioxide has been used as refrigerant in the past and in the last years appears as an option of low impact in the environment. Actually we can use this natural gas in three different ways: systems working with a transcritical cycle, cascade systems or used as secondary coolant.
The most significant characteristic of CO2 are its very high working pressures. Due to the very low critical point, it is impossible to liquefy CO2 over the temperature of 31°C. For such reason has appeared transcritical cycle where the refrigerant loose heat in the high temperature exchanger, but doesn´t change the state. Liquid appear in the expansion. Transcritical cycle is specially used in heat pumps.
In cascade systems we use CO2 as refrigerant in the low stage so it can be condensed at a temperature between 0°C and -10°C.
CO2 as secondary coolant is another application of this refrigerant. It is specially used in supermarkets.
This paper shows the way to implement this application.
In the design of a refrigeration system, the first step is a procedure to establish the amount of heat that has to be removed from a cold store or an equipment to cool or freeze certain products. The components of the refrigeration load are transmission, product, internal and infiltration. This paper describes the method to calculate each component of the heat load based in the ASHRAE Refrigeration Handbook presenting different data to do a the most common types of calculations.
In a vapor compression cycle the refrigerant has a significant role. The efficiency of this cycle depends on the refrigerant properties and these properties will impact in the performance of the refrigeration equipment. The environmental impact of the refrigerants in the atmosphere has led to important changes in the types of refrigerants we use to diminish the direct and indirect impact of them. The use of some refrigerants has created important differences in the refrigeration equipment.
The natural refrigerants look like the best choice to diminish the impact in the atmosphere, but all of them present some problem (toxicity, high pressures, flammability) that has to be specially considered in the design of the systems to avoid further problems. Also a complete new family of refrigerants and mixtures (HFO) has been developed and we need special cares because some of them are flammables.
The presentation also discusses the systems with small charges that will reduce emissions into the atmosphere of halogenated refrigerants used in refrigeration and air-conditioning.
- -R717-Ammonia: the most common refrigerant in Industrial Application since 1860.
- -R744-Carbon dioxide (CO2): very used today in Commercial Refrigeration.
- -R600/R600a-Buthane/Isobuthane: used in domestic applications.