OA20126A - Solar-powered refrigeration systems for medical applications to store vaccines and other intrants, and in agriculture applications to extend the freshness of perishable crops and animal products. - Google Patents

Abstract

This invention focuses on refrigeration targeting the need of those who have no access or no reliable access to electricity. It uses solar electricity to power refrigeration systems with ingenuous local adaptation to the African tropical environment at a much affordable price. This invention targets two specific applications in health centers and agriculture : A-MEDICAL: CONSERVATION FOR VACCINES AND OTHERS The use of autonomous solar powered system for medical application to store vaccines and others such as blood, laboratory reagents, snakes antivenom serums, insulin, antibiotics etc. This invention aims at enhancing vaccine availability, storage and handling using solar powered solutions. It will provide access to vaccines in most remote areas, reduce vaccine waste due to inadequate transportation and storage, and reduce the cost of ownership due to minimal maintenance and functioning cost. Using a rigorous workflow, aligned with the WHO guidelines and calibrated by field data from pilots’ studies, this patent application describes a process that leads to the selection of a solar powered refrigerator or freezer for medical use. In order to remain potent vaccines must be kept at a controlled temperature between +2 °C to + 8 ° C, to achieve that goal this invention focusses on (1) Transformation of a household refrigerator or freezer into WHO standard for vaccine storage system, (2) Solar electricity system to power the refrigerator/freezer, (3) Temperature recorder and display with optional remote wireless alert system, (4) Surveillance and preventive maintenance. The end result is a Solar powered refrigerator or freezer with battery for storage. It is a relatively low-cost system that meets all the WHO performance requirements and suitable for remote underserved locations. B- AGRICULTURE: FRESHNESS EXTENSION FOR PERISHABLE CROPS AND ANIMAL PRODUCTS The use of autonomous solar powered system to extend the freshness of perishable crops and animal products such as plantains, fruits, vegetables, meat, fish, milk etc. In many developing countries, there is a need to strengthen the capacities to contribute to food security and nutrition, by sustainably reducing post-harvest losses, while enhancing market opportunities for their produce. This invention aims to facilitate the development of value chain for perishable crops an animal, by providing a conservation solution that will extend the freshness of food, using solar powered solution. To achieve the technical solution various subsystems, need to work together: (1) Insulated Portable Container, (2) The Cooling Unit, (3) The Solar Power supply, (4) Temperature recorder and display with optional remote wireless alert system, (5) Surveillance and preventive maintenance. The solution provided by this invention applies to: - Perishable crops: vegetables, fruits, and other perishable crops such - Animal produce: meat, fish, dairy produce This solution, that will keep the for perishable crops an animal fresh product at a controlled room temperature between 2 to 10 deg C will extend its freshness by a few days or weeks.

Description

A-MEDICAL: CONSERVATION FOR VACCINES AND OTHERS

The use of autonomous solar powered System for medical application to store vaccines and others such as blood, laboratory reagents, snakes anti-venom sérums, insulin, antibiotics etc. This invention aims at enhancing vaccine availability, storage and handling using solar powered solutions. It will provide access to vaccines in most remote areas, reduce vaccine waste due to inadéquate transportation and storage, and reduce the cost of ownership due to minimal maintenance and functioning cost. Using a rigorous workflow, aligned with the WHO guidelines and calibrated by field data from pilots’ studies, this patent application describes a process that leads to the sélection of a solar powered refrigerator or freezer for medical use. In order to remain potent vaccines must be kept at a controlled température between +2 °C to + 8 ° C, to achieve that goal this invention focusses on (1) Transformation of a household refrigerator or freezer into WHO standard for vaccine storage System, (2) Solar electricity System to power the refrigerator/freezer, (3) Température recorder and display with optional remote wireless alert System, (4) Surveillance and préventive maintenance. The end resuit is a Solar powered refrigerator or freezer with battery for storage. It is a relatively lowcost System that meets ail the WHO performance requirements and suitable for remote underserved locations.

B- AGRICULTURE: FRESHNESS EXTENSION FOR PERISHABLE CROPS AND ANIMAL PRODUCTS

The use of autonomous solar powered System to extend the freshness of perishable crops and animal products such as plantains, fruits, vegetables, méat, fish, milk etc. In many developing countries, there is a need to strengthen the capacities to contribute to food security and nutrition, by sustainably reducing post-harvest losses, while enhancing market opportunities for their produce.

This invention aims to facilitate the development of value chain for perishable crops an animal, by providing a conservation solution that will extend the freshness of food, using solar powered solution. To achieve the technical solution various subsystems, need to work together: (1) Insulated Portable Container, (2) The Cooling Unit, (3) The Solar Power supply, (4) Température recorder and display with optional remote wireless alert System, (5) Surveillance and préventive maintenance.

The solution provided by this invention applies to:

- Perishable crops: vegetables, fruits, and other perishable crops such

- Animal produce: méat, fish, dairy produce

This solution, that will keep the for perishable crops an animal fresh product at a controlled room température between 2 to 10 deg C will extend its freshness by a few days or weeks.

Figure 6: Solar power supply System for walk-in cooler

Fig. 6

O.A.P.I. - B.P. 887, YAOUNDE (Cameroun) - Tel. (237) 222 20 57 00-Site web: http:/www.oapi.int- Email: oapi@oapi.int

APPLICATION FOR A PATENT

Date: 2l-Sep-2020

Location: Yaoundé, Cameroon

TITLE:

Solar-powered réfrigération Systems for medical applications to store vaccines and other intrants, and in agriculture applications to extend the freshness of perishable crops and animal products.

BACKGROUND OF THE INVENTION

Réfrigération is an essential System to modem life. It préserves our food, medicine, and keep our produce cool and fresh. The économie impact of a réfrigération System is deeply rooted in our society, as you can store goods for a long period of time avoiding many logistics and supply and cost issues to hâve them available when needed.

In developing countries, insufficient or non-existent electricity grid power makes it challenging to hâve a functioning réfrigération System. Modem refrigerators, freezer, walk-in coolers all require electricity to function. This application for a patent is focused on an integrated, autonomous réfrigération apparatus for the conservation of goods powered by solar electricity. The resuit is to create a volume where the température is low (e.g. 2 to 10 degrees Celsius) all the time, with monitoring and recording capabilities to validate the températures. The power supply using solar electricity ensures the continuous operation of the System.

With the general goal in mind, this application for invention patent will focus on 2 main applications:

l. Medical samples conservation: The use of autonomous solar powered System for medical application to store vaccines, blood, laboratory reagents, snakes anti-venom sérums, insulin, antibiotics etc.

2. Freshness extension: The use of autonomous solar powered System to extend the freshness of perishable crops and animal products such as plantains, fruits, vegetables, méat, fish, milk etc.

A-Medical: conservation for vaccines and others

On the wake of the Covid-l9 pandémie there is almost certainty that there will be a vaccine to prevent the devastating effect of this pandémie. One of the great public health endeavors is to increase the immunization rate using vaccination from preventable diseases. This issue is acute for children and prégnant women in developing countries especially in rural Africa.

Vaccines are sensitive biological products that can be damaged to varying extents by exposure to freezing températures, to heat and to light. Once vaccine potency is lost, it cannot be regained. Vaccines must be maintained at controlled température between +2 °C to + 8 ⁰ C that is 35° F to 46° F; this requires spécifie logistic adjustments to maintain what is known as “the cold chain”.

This invention aims at enhancing vaccine availability, storage and handling using solar powered solutions. It will provide access to vaccines in most remote areas, reduce vaccine waste due to inadéquate transportation and storage, and reduce the cost of ownership due to minimal maintenance and functioning cost.

The technical solution provided by this invention applies also to storing of any item that requires réfrigération in the health center setting in remote under-served area with limited to no access to grid electricity. This applies therefore to Blood banks, insulin, some antibiotics, snake bites antivenom sérums etc.

From the study conducted in the pilot areas in Africa, one key factor driving the low vaccination rate is the unreliable grid electricity. Vaccines stored in grid powered refrigerators most likely will get spoiled. Using a World Health Organization compatible workflow coupled with collected data, the most appropriate cold storage solution for the evaluated health centers was determined.

The invention is a solar battery powered refrigerator or freezer. A low maintenance, low cost refrigerators with a lifespan of 10 years, with replaceable battery (4-5 years). We concluded that optimum storage capacity should be 50 liters refrigerators to accommodate supply intervals of 3 months. This solution will serve 2,000 children and 500 women of child bearing âge annually per health center. This solution can be scaled up easily to a bigger health center that requires more storing capacity for a larger community.

B- Agriculture: Freshness extension for perishable crops and animal Products

In many developing countries, there is a need to strengthen the capacities to contribute to food security and nutrition, by sustainably reducing post-harvest losses, while enhancing market opportunities for their produce.

In many developing countries, major commodities suffer from an incomplète cold chain. Dairy processors, farmers supplying fruits and vegetable to distant markets, vegetable exporters, slaughterhouses and other aggregators only hâve grid-connected cold storage and may own or hire refrigerated trucks; but small producers do not hâve access to cold storage or refrigerated transport. Grid-connected cold storage réfrigération Systems only work as long as there is reliable electricity; this unfortunately is not usually the case where such Systems are most needed.

This invention aims to facilitate the development of value chain for perishable crops an animal, by providing a conservation solution that will extend the freshness of food, using solar powered solution.

The technical solution provided by this invention applies to:

• Perishable crops: vegetables, fruits, and other perishable crops such as plantains, yams cassava commonly sold in local markets, and yes flowers.

• Animal produce: méat, fish, dairy produce

This solution, that will keep the for perishable crops an animal fresh product at a controlled room température between 2 to 10 deg C will extend its freshness by a few days or weeks.

SUMMARY OF INVENTION

1. A method of selecting a solar System with energy storage battery to power the refrigerator or freezer ln a remote community with little access to electricity from the grid or generator, the options for safe storage in health centers of vaccines, blood, laboratory reagents, snakes anti-venom sérums, insulin, antibiotics etc. corne down absorption type of refrigerator that are powered by fuel or gas, or solar powered refrigerators with or without battery for energy storage.

Using a rigorous workflow, aligned with the WHO guidelines and calibrated by field data from pilots’ studies, this patent application describes a process that leads to the sélection of a solar powered refrigerator or freezer for medical use.

2. An apparatus for réfrigération using refrigerator or freezers

Field data collected from 2019 in pilot area studies in Cameroon Africa, helped in calibrating the conclusions of this section.

The analysis in this section determined that we could transform a chest type (top load) 50 liters (or any other size) quality household refrigerator or freezer into high performance vaccine storage System that meets 12 applicable performance requirements from WHO, at less costly alternative. In addition, a robust compartment température monitoring and logging that can store 3 months’ worth of températures ensure the cold chain is not compromised ensuring the integrity of the vaccines. A solar power supply of electricity ensures the that System opérâtes continuously.

This section will dive into the refrigerator or freezer spécification focusing on: (1) Transformation of a household refrigerator or freezer into WHO standard for vaccine storage System, (2) Solar electricity System to power the refrigerator/freezer, (3) Température recorder and display with optional remote wireless alert System, (4) Surveillance and préventive maintenance.

3. An apparatus for réfrigération using walk-in rooms or containers

There are many solutions available for perishable crops an animal products conservation.

The form and duration of conservation will vary greatly depending on the conservation technique for fruits, vegetable, Milk, méat, fish. The most common types of food conservation are: Smoking, Drying, Dehydrating, Salting, Pickling, Canning, Chilling, Freezing, Food irradiation

The solution that will extend the freshness of the food, without changing it will be cooling or chilling by the means of a réfrigération System. The réfrigération will keep the room at controlled température around 3 degrees Celsius (not freezing). This is the focus of this invention. We will keep the food at such low controlled température environment powered a high efficiency solar System to lower the cost.

The analysis in this section determined that we could transform regular container 20-foot or 40foot container into a réfrigération System that will extend the freshness of the stored perishable crops and animal products

This section will dive into the walk-in cooler components focusing on: (1) Insulated Portable Container, (2) The Cooling Unit, (3) The Solar Power supply, (4) Température recorder and display with optional remote wireless alert System, (5) Surveillance and préventive maintenance.

DETAILED DESCRIPTION OF THE INVENTION

1. A method of selecting a solar System with energy storage battery to power the refrigerator or freezer

From the study conducted in the pilot areas in Africa, one key factor driving the low vaccination rate is the unreliable grid electricity. Vaccines stored in grid powered refrigerators most likely will get spoiled.

This invention aims at enhancing vaccine availability, storage and handling using solar powered solutions. It will provide access to vaccines in most remote areas, reduce vaccine waste due to inadéquate transportation and storage, and reduce the cost of ownership due to minimal maintenance and functioning cost.

This section will cover the solutions available for réfrigération in the context of remote rural areas health care facilities and détermine the best suitable solution. First will be discussed the available solutions and second, we will review the workflow to select the optimal solution for the context.

In such context the following requirements must be met:

• Standalone System independent from the electrical grid and the geographical location The rural areas where this invention is used has no reliable or nonexistent grid electricity. The use of normal refrigerators or freezer powered by grid electricity will not work.

• Minimal to no maintenance required

The remoteness of the health center, access, amenities, communications etc., mandates a System that is very robust and requires little maintenance. Usually there will be no technician nearby or spare parts readily available to repair a broken refrigerator.

• Optimal efficiency

Use as little power as practically possible to run the réfrigération System to drive the cost of ownership as low as possible.

1.1. Available réfrigération solution in the absence of reliable grid electricity

In the absence or insufficient grid electricity, you can substitute the génération of electricity by using a gasoline generator. The fuel to power the generator is expensive for the targeted communities and the access to gasoline is most of the time difficult. The focus is therefore made in selecting a refrigerator that is not powered by the grid nor a gasoline generator. Non-Grid powered refrigerators can be categorized as follows based on how they are powered:

• Absorption refrigerators (much older alternative) o Kerosene powered refrigerators o Liquid Petroleum Gas (LPG) • Solar powered refrigerators o Solar Direct-Drive (SDD): Solar powered, do not use batteries to store energy.

o Solar powered with batteries: Solar powered, with storage battery

l.l.l. Absorption refrigerators or freezers

Immunization programs use refrigerators powered by gas or kerosene (known as “absorption refrigerators”, but there are various disadvantages to using these devices:

• The regular supply of gas or kerosene is expensive for the long term.

• Supply of gas or kerosene is subject to interruption and can be misappropriated by the hospital staff for more lucrative of personal gains.

• Maintaining the “Cold Chain”, which is the System of transporting and storing vaccines within the température range of 2°C to 8°C is challenging for absorption refrigerators.

• Frequent maintenance is required for continuous operation • Operating gas and kerosene refrigerators contribute to local air pollution, and an increase in global greenhouse gas émissions.

An extensive study published in 2019 regarding the cold chain equipment failure in Cameroon* Unveiled that most of the failures were from absorption refrigerators which are currently not currently recommended for vaccine storage

1.1.2. Solar powered refrigerators

Solar refrigerators hâve been providing cooling for immunization programs since early 80s. However, expérience gained over that time has shown that sustained operation of battery powered solar refrigerators is challenging for several reasons:

• Batteries that store solar energy are expensive to replace, sometimes difficult to source, and contain toxic materials that are difficult to dispose of safely.

• Energy from the batteries is sometimes siphoned off for other uses, shortening the life of the batteries and compromising energy needed for cooling.

• Batteries add complexity and the technical expertise required to deal with problems and failures is often lacking in the health centers and communities in which solar refrigerators are placed.

• The capital investment required for battery-powered solar refrigerators is much higher than for absorption and grid-powered options. Battery maintenance and eventual replacement costs add to the overall life cost.

Today, battery technology has evolved significantly to address ail the problems mentioned above. This makes solar powered refrigerators a suitable alternative when grid electricity is not sufficient.

In recent years a new approach to solar refrigerator design has emerged. This new approach éliminâtes the need for energy storage batteries used to power solar refrigerators. “Directdrive” technology uses solar energy to directly freeze water or other cold storage material and then uses the energy stored in the frozen bank to keep the refrigerator cold during the night and cloudy days. These appliances include refrigerators are called solar direct-drive (SDD) because they are wired directly to the photovoltaic generator. A few of drawbacks of the technology:

• The SDD refrigerators are relatively expensive • The solar photovoltaic generator (the size of solar panels array) needs to be high in comparison to the battery powered solar System, sometimes 3 times the size of a battery powered System.

• The system would not run if a minimal power of 70W is not generated • The usable volume of these refrigerators is relatively small because a good part of it is used for freezing lining.

• Might not adéquate autonomy in case of extended cloudy days

1.2. Refrigerator or freezer type sélection workflow based on electricity availability

Figure 1 explains the workflow for the sélection of a refrigerator that is not electricity grid powered. This workflow has been designed based on the reality from most underserved rural remote communities. It is aligned with WHO recommendations and calibrated by field data from our pilot studies in Cameroon in 2019 and other published studies in similar conditions.

Following the workflow, the answers to the questions were:

1. During the last 6 months has there been more than instances of 48 hrs. continuous electricity outage in different months? YES (85%). NO (15%)

2. Is the average daily electrical power outage above 4 hrs? YES (75%). NO (25%)

3. Can a solar powered refrigerator be installed (given initial investment cost)? YES (40%). NO (60%)

4. Are deep cycle batteries readily available? YES (75%). NO (25%)

Using the workflow and based on the answers above the recommendation is to use of solar power refrigerators or freezer for vaccine storage

Amongst the solar powered refrigerators, a choice is between Solar Direct Drive (that does not used battery for energy storage) and Battery powered solar refrigerators (uses batteries to store energy) must be made.

Another look at the sélection criteria is based on cost of ownership

The goal here is to select the vaccine storage solution that provides the lowest maintenance cost (also referred to as lowest annualized life-cost, récurrent cost or operating cost). Such a solution has much chances to be sustained by the health centers after the initial investment is made.

Figure 2 shows an example of how the annualized life-cost of common vaccine refrigerators may be compared, factoring for both capital costs and operational costs. In order words:

In this example, the Ice-Lined Refrigerator (ILR) has the lowest annualized life-cost (Capital and récurrent cost), while the kerosene-fueled absorption refrigerator has the highest annualized life-cost. ILR refrigerators cannot be used because you need to hâve a constant supply of ice. This is not practical because the ice supply is not available in rural area due to lack of electricity to generate it. In addition, the logistics of transporting ice from an available source to the needed area can be overwhelming.

The next best choice now is the Solar powered refrigerators: Solar Direct Drive (SDD), SDD with ancillary battery (for fan and Controls not to store energy), Solar Powered with Battery (to store energy). The SDD refrigerators are the best choice today provided that ail the conditions are met, especially the availability of SDD refrigerators. Using SDD refrigerators could be a challenge because of the capital cost, and vaccine storage capacity. SDD can be 4 to 5 times more expensive for the same storing capacity. As a resuit, solar power refrigerator with Battery is the best option today to store vaccines in most underserved remote rural.

In conclusion, the most appropriate technology for vaccine storage a Solar powered refrigerator or freezer with a battery for energy storage.

2. An apparatus for réfrigération using refrigerator or freezers

The previous section determined the need for selecting a solar powered refrigerator or freezer with battery for energy storage against other alternatives. This section will dive into the refrigerator or freezer spécification focusing on: (1) Transformation of a household refrigerator or freezer into WHO standard for vaccine storage System, (2) Solar electricity System to power the refrigerator/freezer, (3) Température recorder and display with optional remote wireless alert System, (4) Surveillance and préventive maintenance. Figure 3 shows the components ofthe apparatus described in this section.

2.1. Transformation of a household refrigerator or freezer into WHO standard for vaccine storage system

2.1.1. Vaccine storage system size, portability and compartment access

Refrigerator storage capacity

The storage capacity that defines how big the réfrigération system will be varies based on what the amount and type of medical intrant we would like to store: vaccines, blood pouches, snake bites sérums, insulin, antibiotics etc.

The case below depicts the reasoning for a 50 liter refrigerator. It is based on the following parameters resulting from field studies in pilots’ communities: Children vaccinations per health center/year:1388, Women vaccinations per health /year:340, Supply intervals per health /year: 6 (every 2 months). There is a WHO guideline for estimating the refrigerator total volume required based on the type of vaccines used and the number of supply intervals per year; that methodology is illustrated in Table 1.

From the analysis above we can conclude that with a 37 liters’ refrigerator, we can properly store a 2-months’ supply of vaccines in Pilot A. This is enough vaccines to double the current amount plus a 25% safety margin. That means the 37 liters generator has enough capacity to accommodate 1735 vaccinations of children and 425 vaccinations of women.

Looking at standard available refrigerator sizes, 50 liters refrigerator/freezer would be appropriate. If we rerun the simulation above using the WHO guidelines, this could accommodate 3 months stock of vaccines instead of 2 months.

In conclusion, for a community of 2000 children and 500 women, a 50 liters (1.8 cubic feet) refrigerator will be used for this project. It will hold a minimum of 3 months’ supply of vaccine doses per health center.

Top-loading refrigerator/freezer versus front-loading refrigerators/freezer

The sélection here is mostly based on efficiency versus convenience. The energy collected by the solar system needs to be transformed optimally in cooling the refrigerator or freezer.

The front-loading refrigerator or freezer are convenient for accessing the vaccines, however, since heat rises and cold air settles, there is more of a heat exchange on a front-loading refrigerator.

The Top loading refrigerator or freezer (chest type) maintain a more a stable compartment température and is less affected by the door opening from the health staff to access vaccines.

This is illustrated by the fact that in groceries stores fresh or frozen produces are kept in open top réfrigération Systems without affecting the much the compartment température.

Top loading refrigerators or freezers are therefore more efficient at keeping a steady température in the vaccine compartment, and less sensitive to the température fluctuation due to the opening and closing of the doors for vaccine access.

In conclusion we will selecting a top loading refrigerator or freezer for this invention

Portability

Some of the remote areas can only be reached by motorcycle or canoës. A relatively compact and light weight is to be considered for the usable vaccine storage volume.

In our case the 50 liters refrigerator/freezer, the gross volume of the refrigerator is 34Kg, the gross volume is 0.3 cubic meters and the usable volume is 0.05 cubic meters (50 liters), it can easily be transported to the health center in the most remote area by car, motorcycle, canoës, animal back or humans as well.

The 50 liters model used for this application can be used in a moving vehicle as It can be connected to the car 12 Volt battery via a cigarette lighter for example. In most refrigerator or freezer, the unit needs to be in standstill of it to function properly. This is due to the cooling réfrigérant fluid. For the refrigerator we selected for this application, the refrigerator can be used in a moving vehicle and still function properly.

2.1.2. Reliability

Given the remote areas where these refrigerator and freezers will be used, it is impérative to hâve high qualify equipment robust technology that will survive harsh conditions with little maintenance. An extensive study published in 2019 regarding the cold chain equipment failure in Cameroon¹ Unveiled that most of the failures are due to: Faulty thermostat, Cooling unit or Heat resistor

Table 2 illustrâtes the root cause for the failure of 122 Refrigerator in Cameroon in 2019 as part of the study.

The selected solar powered refrigerators use for this invention hâve the following characteristics:

• Super-insulated cabinets feature 11cm of polyuréthane insulation with powdered-coated galvanized steel exterior and aluminum interior.

• A zéro maintenance, brushless, thermostatically controlled DC compresser opérâtes on 12 or 24 VDC.

• Low-frost System reduces frost and moisture build up for low maintenance • This chest-style refrigerator or freezer is easy to clean using the drain hole at the bottom of the unit.

• With thick insulation and a réfrigération System optimized for solar, will provide outstanding economical and reliable operation.

• High-quality construction provides excellent reliability and long life.

¹ Causes of Vaccine Cold Chain Equipment Failure in Cameroon https://jacobspublishers.com/journals/jacobs-journal-of-vaccines-and-vaccination/fulltext/causes-of-vaccine-coldchain-equipment-failure-in-cameroon

This technology allows réfrigération in remote locations where it was previously unavailable or prohibitively expensive

2.1.3. Affordability without compromising the performance requirements

The refrigerator is the single most costly item in the project. It must be selected with great care and a pragmatic mind. A balance between balance between affordability and performance has to be reached. From earlier analysis we derived that the required vaccines storage capacity ofthe refrigerator would be 50 liters (1.8 cu.ft). It was also settled that solar powered refrigerators with batteries will be used.

One more decision needs to be made, a choice between:

• Pre-qualified refrigerators by the World Health Organization (WHO)-PQS • Regular refrigerators (as in Household refrigerators)

A vaccine storage equipment is granted a World Health Organization pre-qualification status under PQS (Performance, Quality and Safety) after meeting a set of standards during a test performed by an approved Laboratory.

Affordability

In Table 3, we compare, at similar volume the cost of WHO Pre-Qualified réfrigération System vs Non-WHO Pre-Qualified ones Quality Household refrigerators.

It is clear from that Table that WHO Pre-Qualified réfrigération System are at least 3 times more expensive than the quality Household réfrigération Systems. This also means that for the same amount of money you can supply 3 more réfrigération Systems to the Health centers.

Performance

This section demonstrates that the sélection of a quality Household refrigerator/freezer, fitted with relatively non expensive but very reliable features can meet or exceed the requirement of the WHO’s PQS (Performance, Quality and Safety) standards.

Table 5 illustrâtes that for ail requirements from the World Health Organization prequalification status under PQS (Performance, Quality and Safety). These applicable performance requirements cover:

1. Operating température range:

2. Réfrigération cycle:

3. Voltage and frequency:

4. Température control:

5. Thermostat:

6. Holdover time:

7. Minimum rated ambient température:

8. Power consumption:

9. Defrost switch:

10. Lock:

11. Corrosion résistance:

12. Manufacturer certification

Ail above requirement hâve been met by our relative low-cost transformed household refrigerators and freezers. Table 5 illustrâtes as well the upgrades that were necessary to meet these requirements.

In conclusion we can upgrade a household grade refrigerator/freezer to meet or exceed WHO’s PQS (Performance, Quality and Safety) standards pertaining to our communities of focus at less than a quarter of the cost.

2.2. Solar electricity System to power the refrigerator/freezer

We hâve established the use of a solar powered refrigerator/freezer with batteries for vaccines storage. This section focuses on how the power is generated to run the réfrigération System. The power génération System needs to take into account the following constraints:

• Cleaner and available electrical energy ail the time • Minimal to no maintenance and expertise from the health staff • Possibility to monitor the functioning of the System even remotely • Availability of ail the power génération components

This invention uses a standalone electrical System powered by the sun. It is an off-grid solar System suitable for remote locations with no available grid electricity. Off-grid power Systems balance electrical génération with use and storage so that electricity can be safely produced, consumed, and stored.

How it works

Figure 4 illustrate the electrical power génération. The main steps are illustrated below:

1. The Sun rays shine on the solar panels generating Direct Current (DC) electricity

2. The DC electricity feeds into charge controller which control the rate at which batteries charge from solar panels.

3. Deep cycle batteries (12 or 24V) stores the energy generated by the solar panels and use it to power the refrigerator

4. The refrigerator/freezer runs directly off the batteries

Below are the main components of the System

The solar panels

The solar panels are put together as an array to produce the energy required to charge the batteries which in turn will run the cooling System. The System voltage is 12 or 24 volts therefore the array of solar panels need to be arranged in sériés and parallel in order to achieve that voltage.

The Panels are installed on the top of the roof of the building usually or on a pôle

Control unit

The control unit in the building close to the refrigerator or freezer. It is made of charge controller, the breakers and the display System. The charge controllers ensures that the batteries are charged properly with the energy from the sun. The whole System is enclosed in a well ventilated and secured metallic box.

Storage batteries

The energy to run the cooling System is stored in the batteries. These batteries that constitute a bank deliverer 12 or 24 volts direct current that powers directly the refrigerator or freezer, the lighting and other electrical needs of the walk in cooler. The batteries are sized to provide at least 5 days autonomy in order to power the System during days when they cannot be charged properly by the solar panels (i.e rainy or cloudy days).

2.3. Température recorder and display with optional remote wireless alert System

Below are the spécifications of the température display and recording of standalone devices. These spécifications help ensure that the température of the walking cooler is within the desired operating range. The recorded data ensure the monitoring, surveillance and the préventive maintenance of the equipment.

• Display of the current température • Display daily highest and lowest températures for the last 30 days • Display the lowest and High and Low alarm status and check alarm status • Continuous monitoring of the température with one reading every 5 minutes • Memory stores températures reading for up to 60 days with one reading every 5 minutes • No need to reset, history automatically erased after 60 days • Operating range -30°C to +50°C hâve to select refrigerator or freezer model • Uncertainty: +/- 0.5°C • Resolution:+/-1.0°C • Battery life up to 3 years, non-replaceable • Track or validate technicians reading températures by using the “read” button of the device • Download data via USB with standard computer; No additional Software, No Cradle or docking station, no additional wires • Report shows the following information:

- Alarm configurations;

- High and low températures

- time outside of the high and low set thresholds • Device créâtes a PDF & Txt; providing the latest 30 days ready to use report and a txt file with 60 days data that can be imported into Excel.

• Détachable température probe, liquid fill vial with 1 meter ribbon wire that fits between opening door gasket.

2.4. Surveillance and préventive maintenance

The températures are downloaded every from the USB port of the température recorder into a data hub or a computer. These data can also be obtained via a wireless connection.

Once the data are in the central location, the are organized so that the user can easily hâve the température history as far back as the data were recorded.

This data allows to do the following:

• Réfrigération System equipment performance over time • Impact of the external température to the functioning of the cooler • Préventive maintenance of the equipment, anticipate on a potential equipment failure

3. An apparatus for réfrigération using walk-in rooms or containers

There are many solutions to conserve perishable crops and animal products like fruits, vegetable, Milk, méat, fish. The most common types of food conservation are: Smoking, Drying, Dehydrating, Salting, Pickling, Canning, Chilling, Freezing, Food irradiation.

Not ail conservation techniques are readily applicable in developing countries for our local food production. Food irradiation (the application of ionizing radiation to food) is a technology that improves the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects. Even though the irradiation technique is very effective, It is hard to imagine our local farmers using Gamma rays, X-rays or Electron beams using any of these 3 sources of radiation approved for food.

Depending on the food type, various methods are available:

Méat and fish conservation today are mostly smoking, salting, brining, canning, freezing and dehydrating are great options to help you keep méats available for future meals.

Fruits and vegetable conservation usually require one of these methods: Freezing, drying, Pickling or canning.

Milk conservation usually requires one of these methods: salting, dehydrating, pasteurizing, freezing and canning.

Table 4 shows food conservation technique for perishable crops and animal products

The only solution that extends the freshness of méat, fish, fruits and vegetable and milk is refrigerated cooling or chilling. That is keeping the food in a controlled température close to 3 degrees Celsius. It addresses the problem of post-harvest losses in fruits, vegetables and other perishable food. It can be installed in major food production centers (farms) and consumption centers (in markets). The products can be stacked in crates or shelves. This solution can extend the freshness of fruits, vegetables and other perishable food from a few days to more than 3 weeks

In many cities and rural area, access to continuons and reliable electricity from the grid or generator is difficult. As a resuit, the use of a typical generator or walk-in cooling room to extend the freshness of the produce is challenging. As a resuit, even grid connected cold storage Systems are compromised.

The solution is the use of a solar powered System. For high efficiency, a Direct Current (DC) instead of a common AC (Alternative Current) is used.

In summary the solution to extend the freshness of perishable crops and animal products such as fruits, vegetable, Milk, méat, fish is a used of a walking cooling refrigerated System, with a controlled température around 3 degrees Celsius powered by solar electricity with build in Direct current components for high efficiency.

This section will dive into the walk-in cooler components focusing on: (1) Insulated Portable Container, (2) The Cooling Unit, (3) The Solar Power supply, (4) Température recorder and display with optional remote wireless alert System, (5) Surveillance and préventive maintenance.

Figure 5 shows the portable container size réfrigération System described in this section.

3.1. Insulated Portable Container

3.1.1. Portable container

The volume to be cooled is a confined spaced that can be transported from one location to another. The solution used in this application is any combination of shipping container of 20 feet or 40 feet. They can operate on a given location for weeks months or years. When it is time to move to another location, ail the equipment and essentially the solar panels are disconnected and packed for transportation. The transportation of the container is done via a trader where the empty container is loaded using a skid, a crâne or fork lift. For remote locations where crâne or forklift are not available, use of a tilt bed trader; its flatbed that can be tilted ail the way to the ground level to load or offload the container.

3.1.2. Container insulation

Insulation will help keep the température down by insulating it from the outside ambient température. It will help lower the energy required to cool the unit. Insulation is measured by its R-value, which tells you the capacity of the insulation to resist heat. The higher the value, the more effective the insulation. The industry standard for walk-in coolers is R25. Going up to R30 is optimal for this case as we want to keep our cooler température especially if you are keeping your cooler at 3°C range.

There are two solutions to use for this insulation: Do the full insulation of the container from a standard shipping container that does not hâve insulation or use an existing refrigerated container, used or new that has already been insulated without the cooling System.

Insulating a normal shipping container

There are several types of insulation you can use in your walk-in cooler. The use of rigid foam whenever possible is recommended- polyisocyanurate on the walls and ceiling and extruded polystyrène on the floor. Polyisocyanurate, R-Max is the most recommended insulation because it has the highest R-value per inch of thickness and is reasonably priced. 10cm of RMAX typically exceeds the required R25. Extruded polystyrène or XPS, XPS has an R-value of 5 per inch of thickness requiring 12cm of insulation to achieve R-25

Proper sealing is essential for the insulation to function efficiently; even the smallest hole can hâve a large impact on your cooler’s energy efficiency. Sealing joints between the walls, floor, and ceiling and gaskets on the doors is performed using spray foam. A weather stripping or a rubber gasket is used for a door tight seal if needed.

The container shipping door can be modified for easy accessibility. As far the insulation is concerned the following steps must be taken: (1) the door opens to the outside of the container and that it can swing freely, (2) glue the same type of insulation on the wall on the doors as well, (3) use plastic curtains and automatic door closers to limit cold air loss when the door opens, Using a refrigerated container (reefers)

A refrigerated shipping container is already insulated. They are a crucial part ofthe “cold chain”, a parallel supply chain that handles temperature-controlled goods. Products like méat, dairy, fruits, vegetables, and even flowers and pharmaceuticals often dépend on the cold chain.

Refrigerated containers hâve spécial métal (usually aluminum) floors. This flooring System, called a T-floor, has a T-shaped profile that keeps the contents of the container elevated so that cold air can flow underneath. Refrigerated containers hâve walls made of a sandwich of durable materials on both sides of the insulation. This sandwich is typically made of stainless-steel panels on both the interior and exterior with a thickness of 0.8 to 1,2mm. The exterior is often painted white, while the interior may be left uncoated.

The wall thicknesses of insulated containers depending of their class, is between 9cm and 11cm and their R-value (insulation) is between 27 and 33 with is good for the intension of this application.

The last two feet of the container is dedicated to réfrigération equipment, for the purpose of this invention, the original equipment is removed and replaced with the solar powered réfrigération equipment that will fit in the same space.

3.2. The Cooling Unit

3.2.1. The mini-split direct currentpowered Air Conditioning (AC) System.

Mini splits air conditioning (AC) Systems are streamlined and compact, consisting of two discrète components—an outdoor condenser and an indoor unit. The AC Systems used are engineered from the ground up for use with direct current (DC) therefore for the use of solar energy without the need of an inverter to couvert the energy back to alternative current before it is used. The AC System uses 48 volts direct solar or battery power with a 12,000 BTU Heat Pump. This is enough capacity to cool 160 m3 of volume (about 65m2 of footprint in 2.5m height). The AC System will be sized enough to cool the 72 m3 volume of 40ft container.

Spécial electronics anticipate and smoothly handle voltage fluctuations of up to 38% without affecting the operation. In addition to the compresser and control circuits, ail other electrical components are DC powered including DC fan motors, DC valves & solenoids, etc. The brushless DC compressor and fan motors we use provide a soft-start which means that the typical startup surge of an AC air conditioner running on an inverter is eliminated. A normal air conditioner will draw up to 500% more amps on startup, meaning that when running on an inverter, the inverter must be oversized accordingly. Oversized inverters are much less efficient.

The condenser unit of the AC is placed outside the container. When using a refrigerated container, it is placed on the extra 2 foot (0.6 meter) of space at the end of the container. A pair of réfrigérant pipes connect that unit to the indoor unit that has the evaporator. The evaporator unit is mounted on the small length, of the container so that it blows down the length of the container. In addition the evaporator unit should be mounted as high as possible as the cold air sinks; the bottom of the unit at should be at eye level.

3.2.2. Bring down the température with a température regulator

Air conditioners (AC) are not designed to operate in or produce températures below 15 degrees Celsius. In order to cool the container to much lower températures down to 2 degrees Celsius, an electronic température regulator is used in conjunction with the AC. The desired room température is set on the regulator display for example 4 degrees Celsius to keep vegetable fresh.

The sensors used by the regulator are:

• A fins sensor is connected to the fins of the evaporator coil of the AC unit. It monitors the coldest températures point generated by the AC unit and feeds back to the regulator.

• A heater cable that is connected to the AC température sensor. The heat cable heats up the AC température sensor making the AC operate as if the room is hotter that it actually is, therefore getting the compresser to work harder in cooling the room.

• A room température sensor measures the température of the room and provides feedback to the température regulator device.

The regulator that consumes minimal power forces the AC to operate at a different set point and bring down the room température.

3.3. The Solar Power supply

This is a standalone electrical System powered using the energy from the sun to power the walking cooler. It is an off-grid solar System suitable for remote locations with no available grid electricity. Off-grid power Systems balance electrical génération with use and storage so that electricity can be safely produced, consumed, and stored.

The power génération System needs to take into account the following constraints:

• Cleaner and available electrical energy ail the time • Minimal to no maintenance from the operating staff • Possibility to monitor the functioning of the System even remotely • Supply availability of components required for the System • The System should be suitable to run the Air Conditioning unit that requires 48 volts of direct current to operate. Therefore, the voltage of the System will be 48 volts.

Figure 6 illustrate the electrical power génération. The main steps are illustrated below:

1. The Sun rays shine on the solar panels generating Direct Current (DC) electricity

2. The DC electricity feeds into charge controller which control the rate at which batteries charge from solar panels.

3. Deep cycle batteries store the energy generated by the solar panels and use it to power the refrigerator

4. The Walk-in cooler runs directly off the batteries

3.3.1. The solar panels

The solar panels are put together as an array to produce the energy required to charge the batteries which in turn will run the cooling System. The System voltage is 48 volts therefore the array of solar panels needs to be arranged in sériés and parallel in order to achieve that voltage.

The Panels are installed on the top of the container, they are prewired and with a tilting System up to 20 deg from the horizontal. The panels can be dismantled and stored inside the container for long distance trips.

3.3.2. Control unit

The control unit just like the batteries are situated at the back of the container. It is made of charge controller, the breakers and the display System. The charge controllers ensures that the batteries are charged properly with the energy from the sun. the whole System is enclosed in a well ventilated and secured metallic box.

3.3.3. Storage batteries

The energy to run the cooling System is stored in the batteries. These batteries that constitute a bank deliverer 48 volts direct current that powers directly the air conditioning System, the lighting and other electrical needs of the walk in coder. The batteries are size to provide a 2 or 3 days autonomy in order to power the System during days when they cannot be charged properly by the solar panels (i.e rainy or cloudy days).

3.4. Température recorder and display with optional remote wireless alert System

Below are the spécifications of the température display and recording of standalone devices. These spécifications help ensure that the température of the walking cooler is within the desired operating range. The recorded data ensure the monitoring, surveillance and the préventive maintenance of the equipment.

• Display of the current température • Display daily highest and lowest températures for the last 30 days • Display the lowest and High and Low alarm status and check alarm status • Continuous monitoring of the température with one reading every 5 minutes • Memory stores températures reading for up to 60 days with one reading every 5 minutes • No need to reset, history automatically erased after 60 days • Operating range -30°C to +50°C hâve to select refrigerator or freezer model • Uncertainty: +/- 0.5°C • Resolution:+/-1.0°C • Battery life up to 3 years, non-replaceable • Track or validate technicians reading températures by using the “read” button of the device • Download data via USB with standard computer; No additional Software, No Cradle or docking station, no additional wires • Report shows the following information:

- Alarm configurations;

- High and low températures

- time outside of the high and low set thresholds • Device créâtes a PDF & Txt; providing the latest 30 days ready to use report and a txt file with 60 days data that can be imported into Excel.

• Détachable température probe, liquid fill vial with 1 meter ribbon wire.

3.5. Surveillance and préventive maintenance

3.5.1. Température surveillance

The températures are downloaded every from the USB port of the température recorder into a data hub or a computer. These data can also be obtained via a wireless connection.

Once the data are in the central location, the are organized so that the user can easily hâve the température history as far back as the data were recorded.

This data allows to do the following:

• Réfrigération System equipment performance over time • Impact of the external température to the functioning of the cooler • Préventive maintenance of the equipment, anticipate on a potential equipment failure

3.5.2. Température surveillance

Electrical parameters such as daily voltages, currents, energy produced by the solar panels, energy consumed by the réfrigération System are downloaded dedicated communication ports. The data can be centralized into a local computer or a centralized location (hub). These data can also be obtained via a wireless connection.

This data allows to do the following:

• Monitoring of the System health • Préventive maintenance of the equipment, anticipate on a potential equipment failure

TABLES

Tables’ Summary

Table 1: Estimation of the refrigerator size in liters (L) for a 2 months interval supply for 1388 children and 340 prégnant women vaccinated a year in Pilot A study conducted in Cameroon in 2019

Table 2: Root cause for the failure of 122 Refrigerators in Cameroon in 2019 as part of a study published in Jacobs journal of Vaccines and vaccination

Table 3: Cost comparison of refrigerator based on World Health Organization (WHO) certification status

Table 4: Food conservation technique for perishable crops and animal products

Table 5: Illustrâtes that for ail requirements from the World Health Organization prequalification status under PQS (Performance, Quality and Safety).

Table 1: Estimation of the refrigerator size in liters (L) for a 2 months interval supply for 1388 children and 340 prégnant women vaccinated a year in Pilot A study conducted in Cameroon in 2019

Vaccine	Children and Women vaccinated per year	Doses per year per vaccine	Annual number of doses	Number of supply intervals per year	Number of doses per supply interval	Packed vaccine volume per dose (cm3/dose)	Packed vaccine volume per dose, diluent (cm3/dose)	Vaccine storage volume, vaccine (L) +2°C to +8°C	Vaccine storage volume, diluent (L) +2°C to +8°C
BCG	1388	1	1388	6	231	1.2	1.1	0.3	0.3
DTP-HepB,Hib-IPV	1388	3	4164	6	694	11.3		7.8
Measles	1388	1	1388	6	231	2.4	3.2	0.6	0.7
OPV	1388	3	4164	6	694	2		1.4
PCV13	1388	3	4164	6	694	13.8		9.6
Rotavirus vaccine	1388	2	2776	6	463	17.13		7.9
TT	1728	1	1728	6	288	3.11		0.9
Yellow fever	1388	1	1388	6	231	0.5		0.1
Total vaccine volume per supply interval (L)								28.6	1.0
Volume of 25% safety stock (L)								7.1	0.2
Cold chain capacity requirements (L)								35.7	1.2
Cold chain capacity requirements (L)									37.0

Table 2: Root cause for the failure of 122 Refrigerators in Cameroon in 2019 as part of a study published in Jacobs journal of Vaccines and vaccination.

Cause of failure	Count
Single fault
Improper Thermostat adjustment	40
Faulty cooling unit	21
Faulty thermostat	19
Faulty heat résister	14
Réfrigérant leak	7
Faulty compresser	3
Faulty electronic control unit	2
Double faults
Faulty thermostat and heat résister	13
Faulty heat résister and pressure regulator	2
Faulty compresser and electronic control unit	1

Table 3: Cost comparison of refrigerator based on World Health Organization (WHO) certification status - Price check in 2019

Qualification by WHO	Solar power type	Refrigerator	Vaccine capacity	Cost (USD)
WHO Pre-Qualified	Solar direct-drive batteryfree technology	Manufacturer 1	55 liters/1.9 eu. ft.	$3,700
WHO Pre-Qualified	Solar powered with storage batteries	Manufacturer 2	37.5 liters/1.3 eu. ft.	$4,100
Not WHO Pre-Qualified	Solar powered with storage batteries	Manufacturer 1	50 liters/1.8 eu. ft.	$700

Table 4: Food conservation technique for perishable crops and animal products

Conservation techniques	Fruits	Vegetable	Milk	Fish	Méat
Smoking					X
Drying					X
Dehydrating	X	X	X		X
Salting			X		X
Pickling	X	X
Canning	X	X	X		X
Chilling	X	X			X
Freezing	X	X			X
Irradiation	X	X			X

#	Main applicable Performance Requirements	Solution
1	Operating température range: As indicated on the température zone rating sticker attached to the product (see Annex 1).	Yes
2	Réfrigération cycle: Compression-cycle unit, with one or two compressors, operating on direct current electricity	Yes
3	Voltage andfrequency: Generally, 12-24 volt DC, supplied from a solar powered battery set. Other voltages may be acceptable	Yes, 12-24 Volt DC
4	Température control: Refrigerator compartment: The entire vaccine load must remain within the acceptable température range. The acceptable température range for storing vaccine is +2°C to +8°C. However, transient excursions outside this range will be tolerated, within the following limits: • No excursion must exceed +20°C. • No excursion must reach 0°C	Yes, +2°C to +8°C
5	Thermostat: The thermostat must be set to prevent freezing in any part of the vaccine storage compartment. It must be designed so that it cannot be adjusted by the user. A means for adjustment by a technician is acceptable provided the device is protected from user interférence (e.g. by location within the appliance cabinet). Alternatively, programmable thermostats may be password-protected	Yes ; The setting knob of the thermostat moved at the back of the refrigerator so that it cannot be accessed by the user, a protective box with a key protects the dial setting of the thermostat
6	Holdover time: Holdover time is the time in hours during which ail points in the vaccine compartment remain between +2°C and +10°C, at the maximum ambient température of the température zone for which the appliance is rated, after the power supply has been disconnected. The recommended minimum holdover time is 3 hours.	Yes, above 3 hours
7	Minimum rated ambient température: Ail models will be tested to establish their minimum rated ambient température. The minimum acceptable performance rating is achieved if the product passes the day/night test for its nominal température zone. The maximum performance rating is achieved if the vaccine load remains within the acceptable température range at -10°C. A freeze-prevention circuit may be required to protect against freezing at low ambient températures	Not applicable for the targeted area subjected to tropical weather where the température does not go below freezing
8	Power consumption: To be less than 0.7 kWh per 24 hours for appliances with a gross volume of less than 50 litres and less than 0.1 kWh per additional 10 litres gross volume, with a full vaccine load, but without waterpack freezing.	Yes, Current refrigerator: uses 0.1 !4kWh per 24hrs at 32degC
9	Defrost switch: The defrost switch (or switches if dual compressors are employed) must accessible to the user without tools but must be protected from accidentai changes in position.	Yes. A patented low-frost System reduces frost and moisture build up for low maintenance.

10	Lock: The door or lid must be fitted with a lock. Two keys are to be supplied with every unit.	Yes
1 1	Corrosion résistance: Internai and external cabinet, lid and frame protected against corrosion	Yes. Powder-coated galvanized Steel exterior Aluminum interior
12	Electrical safety rating: Manufacturer to certify compliance with IEC 60335-1 and 1EC60335-2-24.	Manufacturer certified for ISO-9001:2015

Table 5: Illustrâtes that for ail requirements from the World Health Organization prequalification status under PQS (Performance, Quality and Safety).

Claims (6)

CLAIMS Claim 1: A method of selecting a solar System with energy storage battery to power the refrigerator or freezer, characterized by:

1. An insulated container portable container;

1. A réfrigération unit (refrigerator or freezer) powered by direct current;

1. The use of last 6 months and daily grid electricity availability;

2. A direct current (DC) Air conditioning cooling System with feedback loop;

2. A solar electrical System that powers the réfrigération unit;

2. The affordability to invest in a solar-powered réfrigération with storage batteries;

3. A température display and recording unit with alarms that records températures;

3. A température display and recording unit with alarms that records températures;

3. The access to deep cycle batteries for energy storage.

Claim 2:

An apparatus for réfrigération using refrigerator or freezers that ensures stable température, according to claim 1 characterized by:

4. A solar electrical System that powers the réfrigération unit;

4. A monitoring service System that allows to track températures for months or years; making the manual daily record of températures redundant.

Claim 3:

An apparatus for réfrigération using walk-in rooms or containers that ensures stable température, according to claim 1 characterized by:

5. A monitoring service System that allows to track températures for months or years making the manual daily record of températures redundant.

FIGURES

Drawing’s summary

Figure 1: workflow for selecting a solar System with energy storage battery to power the refrigerator or freezer

Figure 2: Example average estimated annualized cost for purchase, installation and maintenance of WHO prequalified refrigerator types

Figure 3: An apparatus for réfrigération using refrigerator or freezers that ensures stable température

Figure 4: Solar electricity power System for refrigerator or freezer

Figure 5: An apparatus for réfrigération using walk-in rooms or containers that ensures stable température

Figure

6: Solar electricity power System for portable container