Post00385 HYBRID SOLAR AND COOL IDEAS + PIS

Post00385 HYBRID SOLAR AND COOL IDEAS + PIS 19 October 2001 CONTENTS 1. HYBRID SOLAR ELECTRIC POWER continued 2. RE: Post00383 COOL IDEAS continued 3. THE PRODUCT INFORMATION SHEETS (PIS) Visit the TechNet 21 Delhi meeting web pages at: http://www.who.int/vaccines-access/index.html Get the latest Technet21 documents at: http://www.who.int/vaccines- access/Vaccines/Vaccine_Cold_Chain/Technet/2001_Delhi_Technet.htm ____________________________________*______________________________________ 1. HYBRID SOLAR ELECTRIC POWER continued In Post00382, 9 October 2001, John Lloyd, PATH/CVP asked: "Does anyone have experience of 'hybrid' systems that run on PV panels and batteries but which also run on grid electricity when it is available? Seems to me that such systems might work well in areas with a bit of electricity." In todays posting Terry Hart, IT Power India, identifies a 5 year old working installation and comments on projects under development. See item 2 in this posting for a related message. * Replies to: [[email protected]][email protected][/email] or use your reply button! ___________________________________________________________________________ Moderators note: Hybrid systems are applicable to the very many rural places with locally generated electricity that is available for a few hours or as many as 6 hours. ___________________________________________________________________________ From: "Terry Hart" To: "'Technet Moderator'" Subject: RE: Post00382 SOLAR + Date: Wed, 10 Oct 2001 Hi John/Allan, IT Power India has some experience, and there is one plant in Nepal at a DHQ near to the refugee camps in Biratnagar which was financed by UNHCR 5 years ago. The site is still function despite zero maintenance since installation. Batteries are now tiered however. ITPI is working with Soren Spanner at WHO/SEARO to put together a pilot project in Sri Lanka and we are currently formulating a proposal for a project in another country. We have been working towards getting some pilot sites up and running for about 1 year now (or more). Earlier delays beyond our control prevented us from moving forward, but now the channels have cleared. We have lots of info on modelling, hybrid mixes etc etc Best regards terry ____________________________________*______________________________________ 2. RE: Post00383 COOL IDEAS continued These contributions from Ian Wyllie, SOTON, discusses solar powered absorption refrigeration and makes some constructive suggestions on the WHO Product Information Sheets. Kirsten Myhr, RE/UUH, continues the discussion of COOL IDEAS from Post00383 and Post00384, by calling on a friend in a sunny place! Contributions to: [[email protected]][email protected][/email] or use your reply button! ___________________________________________________________________________ From: "Ian Wyllie" To: "Technet Moderator" Subject: RE: Post00383 COOL IDEAS Date: Wed, 17 Oct 2001 Dear Allan, I read the notes on the solar absorption refrigerator with interest. I have some comments, which may be of interest to the community. I don?t know what the rules are on citations, copyright citations etc, so perhaps you can put a statement with the reference ? if it is required. SUMMARY: Discussion of practical problems with the implementation of Solar Powered Absorption refrigeration Discussion of the reasons why this and other technologies have not found broader application in the EPI family, and of the effectiveness of EPI specifications in limiting innovation. COOL IDEAS (POST00383) COOLED BY THE SUN 06 Oct 01 Vaccines and medicines need to be stored in cool places-not so easy to find In parts of the world with no access to electricity. To preserve vaccines in hot conditions, scientists at the University of Jordan have designed a cooling cabinet that runs on solar energy. The unit uses the familiar ammonia absorption cycle for refrigeration-ammonia is driven out of an aqueous solution by the Sun's heat, and is then condensed and circulated back into solution through an evaporator. The designers particularly want to improve healthcare for nomadic tribes. From New Scientist magazine, vol 172 issue 2311, 06/10/2001, page 24 ? Copyright New Scientist, RBI Limited 2001# * Firstly the original paper is: Design and performance study of a solar energy powered vaccine cabinet M. Hammad*, S. Habali University of Jordan, Faculty of Engineering and Technology, Amman 11942, Jordan In: Applied Thermal Engineering 20 (2000) 1785?1798 http://www.elsevier.com/locate/apthermeng This journal is freely available online and anyone interested in this development should read consider reading the original paper. * Secondly, some comments on Absorption Refrigeration powered by solar collectors: 1. There has been significant interest in this field for a number of years (since at least 1986) but relatively few commercially viable systems have been implemented in less developed areas. Why this is curious, because the technology has the potential to be of great use in the field especially as Hammad and Habili point out if the technology could be made truly mobile. This leads me to consider a number of reasons why the technology has not been more widely adopted: A: Solar collector technology is by its nature not robust. Flat plate collectors relatively simple, although the evacuated tube collectors used in them are extremely fragile, but there relatively low efficiency means that the sizes of collector field involved becomes cumbersome for even small systems. I note that Hammad and Habili base their design on an alignable cylindrical solar collector. This is a simple and effective system, however the requirement for it to be correctly aligned, and for it to be regularly realigned during the year pose training challenges more complex than those found with PV systems. COMMENT: The fragility, relatively large size, and the training load associated with solar collectors are probable significant factors in the lack of enthusiasm for this type of technology B: The technology of solar absorption refrigeration is an intermittent cycle, because the power is only available during a portion of daylight hours. Therefore the temperature control for the majority of the working life of the system will be based on the amount of energy stored during the operating day, which is a system variable directly proportional to insolation. This means that a period of reduced insolation is likely to cause a breakdown in the cold chain, because the system does not incorporate any long term or reserve energy storage. COMMENT: Therefore, unless this system is placed at a site in conjunction with other systems that are capable of providing assured refrigeration there has to be a question over the effectiveness of service it will provide. I note that here also there will be issues with training, because the concept of an intermittent system does not have any analog among equipment currently in use, indeed comparison with the existing KeroseneLPG fueled absorption systems could cause confusion. Effective management of this type of system requires thermodynamic understanding, which it may not be possible to communicate effectively in the available time frame to the technicians and healthcare workers responsible for it. C: Consideration of the WHO EPI product testing specifications indicates that it might be impossible to develop a solar powered absorption system which would meet any one of the individual specifications in WH0, WHO/EPI/LHIS/97 "EPI Equipment Performance Specifications," and therefore, without an assured market, the likelihood of any engineering company being willing to commit to the innovation and development required to bring such a specialist product to market is extremely limited. COMMENT This is it occurs to me a more generally applicable point. EPI/LHIS/97 is framed to produce the equipment currently approved for marketing through the Product Information Sheets. Now, this equipment has been developed to allow the implementation of what might be characterised as the "generic" EPI programme customised of course to local needs. However, the recent interest in the development of more flexible cold chain policies, and innovation in that area is likely to result in limited change unless engineering companies are encouraged to study product flows in the cold chain, to consult with the user community to determine their needs, and then to produce products meeting those needs ? even if they do not fit into the current model of cold chain delivery. Perhaps a set of less specific and more general specifications should be issued covering ranges of the cold chain defined according to category ? perhaps "outreach and health centre refrigeration" "District level, and Hospital" and "Central Logistics Node." The specifications could state the end outcomes required, in terms of temperature stability, volume and robustness, without constraining innovation, in for example the integration of power sources into a single system. CONCLUSION I believe that there are vital roles for solar absorption refrigeration to play, in conjunction with other systems to allow the delivery of effective primary health care. Personally I believe that they will be most effectively employed in ice production at important, but possibly temporary logistic nodes, for example during vaccination campaigns, or to support stored cold refrigeration where there is a high density of clinics in an area lacking infrastructure, for example an area of refugee or IDP settlement, I believe that commercial development of the systems has been limited because of over constraint in the drafting of specifications. Potentially contentious thoughts? I await critical comments, contributions or other responses with interest. Ian Wyllie Design Study on Medical Products Refrigeration for use in Relief and Development Settings Faculty of Engineering and Applied Science University of Southampton Southampton SO17 1BJ The views expressed in this e-mail are those of the author alone and not necessarily those of the University of Southampton. ___________________________________________________________________________ From: Kirsten Myhr To: "'Technet Moderator'" Subject: RE: Cool ideas and Hybrid solar Date: Thu, 18 Oct 2001 21:08:05 +0200 Allan, I used again my source in a sunny developing country who knows quite well power sources and options to comment on the cool idea and the hybrid solar. Regards Kirsten Myhr This is his response: HYBRID SOLAR ''Hybrid solar systems use both available sunlight and available mains electricity to charge batteries, and can provide very reliable power under appropriate conditions including limited hours of electricity and or sunlight''. By definition "mains electricity" means connected to a national grid or small town power station - in which case solar is outlandishly expensive - no one in their right mind would add solar power to a mains system! If there is mains on for 8 or 12 hours a day (as in a small town / rural community) then big batteries & a big charger is the answer - solar is presently the most expensive form of power available (wind power is cheaper). If one is going to install a small generator (to run 3 or 4 hours a day) - then put in a slightly bigger one and go the route of charger and batteries again - solar is the last option again. Please do not misunderstand me - I would love the whole world to run on solar - it is clean, quiet and very low maintenance but one must be realistic - it is still too expensive - particularly in poorer rural areas. The expense is in the capital outlay - it is easy for a first world inhabitant to calculate that after the system has been in for 3 or 5 years it is "free" because of almost zero maintenance but the third world person simply can not afford it in the first place. We find it very difficult to sell our solar water pumping systems against diesel/petrol pumps and our clients do immediately see the long term advantages but it is only the more affluent ones that can afford the capital outlay - so; the rich can afford to benefit and the less fortunate just have to struggle on. --- Does anyone have experience of 'hybrid' systems that run on PV panels and batteries but which also run on grid electricity when it is available? See above - "grid" electricity implies a constant supply or a big central generator set, power station or national grid - then one would use a suitable charger and bank of batteries - solar is not an economic option - not even close!!! Seems to me that such systems might work well in areas with a bit of electricity. Point me at an area with "a bit of electricity" - you either have it or do not have it! ''Fridges waste a lot of energy cooling down after the door has been opened, says Hitachi of Japan. So in its latest fridge, the firm has placed a small door within the big door for those often-taken-out items, such as milk. In tests, the idea has cut the amount of escaping cold air by 90 per cent, Hitachi says''. Very true - an excellent idea ! --- COOLED BY THE SUN 06 Oct 01 ''Vaccines and medicines need to be stored in cool places-not so easy to find in parts of the world with no access to electricity. To preserve vaccines in hot conditions, scientists at the University of Jordan have designed a cooling cabinet that runs on solar energy. The unit uses the familiar ammonia absorption cycle for refrigeration-ammonia is driven out of an aqueous solution by the Sun's heat, and is then condensed and circulated back into solution through an evaporator. The designers particularly want to improve healthcare for nomadic tribes''. They are dreaming again! Now - this is an application where photovoltaic solar is the best option. Consider the following:- a) Absorption fridges are pathetically inefficient - even when heated by LP gas they are not wonderful. They have to be kept exactly level (difficult if it gets moved by nomads quite often) and rely heavily on temperature differentials - ambient temperatures are critical. In hot climates a water evaporation cooling system is often better. The solar heat "gathering device" would be critical - if it is a dish or similar it would have to be moved to follow the sun all day..... b) A solar array filling batteries or directly driving a commercially available 12 volt DC fridge compressor (like the Engle fridge from Japan, the Minus 40 fridge from South Africa or several from Australia ) is a very efficient unit that is robust and not subject to the same level constraints, etc. Most of these units have good "hold over" capabilities to keep contents cool over warm nights....... The absorption may be cheaper but if it does not work - what use is cheap ? ____________________________________*______________________________________ 3. THE PRODUCT INFORMATION SHEETS (PIS) ___________________________________________________________________________ The Product Information Sheets (PIS), provides general information on the choice of equipment, together with specific technical and purchasing data for individual selected items. Product Information Sheets, 2000 edition (WHO/V&B/00.13) http://www.who.int/vaccines-documents/DocsPDF00/www518.pdf This is the 12th edition of the Product Information Sheets, produced by the WHO Expanded Programme on Immunization (a team under the Department of Vaccines and Biologicals) in collaboration with the Supply Division of UNICEF (Copenhagen) on a regular basis since 1979. The PIS was formerly concerned only with equipment for the Expanded Programme on Immunization (EPI). From the 1993/1994 edition onwards the scope was expanded. This edition includes equipment from the programme to reduce Acute Respiratory Infections (ARI) as well as equipment to be used in emergency campaigns and for other primary health care initiatives. For the EPI, this edition includes the standard selection of cold chain equipment for the storage, transport and administration of vaccines, as well as equipment for the collection and transport of stool specimens for the isolation of polio virus. A new section, Waste Disposal, has been added to this edition. This section includes all the previously listed safety products from the section E10 on Injection Accessory, and some new products. These products have been given their own section in order to highlight the importance of safe injections in immunization services, a priority project of WHO. For the EPI equipment, standards for performance and testing of EPI equipment are contained in a series of WHO/EPI documents, Equipment performance specifications and test procedures. These publications which were prepared for use by manufacturers in the international market, provide clearly defined blueprints for the production of equipment that will meet the highest competitive standards of reliability and performance in the EPI. http://www.who.int/vaccines- access/Vaccines/Vaccine_Cold_Chain/Equipment/PIS/Specs&Procs.htm ____________________________________*______________________________________