Hi there,
I don't have an electrical background (mechanical engineer) though currently find myself in Sri Lanka, working for a local NGO on off-grid electricity projects for the rural poor, and could really use your help.
Small, village-run micro-hyro plants of around 10-20kW are a mature solution here for getting power to isollated mountain communities. They provide between 100-400W peak power, per household, via a simple mini-grid. While 10 years ago when these projects began, villagers were happy to recieve this humble amount of power, their aspirations have grown. Now, the use of power-hungry western appliances is causing friction due to the lack of available capacity for all.
My main focus is to look technically and socially at the best ways to distribute what power there is fairly. At present there are no meters and a flat monthly tariff. Simplicity, reliability and minimal-cost are the key drivers as I'm sure you can guess.
If I get any response on this I should maybe split my ideas into different posts but for now I'll just go through them:
1. Working with the exisiting (very simple) household fuse-box, I'd like to wire in a 24 hr timer that runs on scavenged power (very low consumption) and that has battery backup, as power cuts are common. This clock (manual or digital whatever is cheapest) will be programmed to switch a relay or contactor that will re-route mains power from a 200W circuit breaker through a 700W circuit to correspond with peak (evening) and off peak (daytime) power capacity. The idea is to bar overuse of the agreed household power allocation.
Honesty is an issue, so the clock will be simply secured, though I'd like the family to be able to reset the circuit breakers if overuse is accidental. The village prefer fuses ... Does anyone know whether circuit breakers can be manually overridden or not ? (provided they cannot be removed).
Can anyone advise me on the technical feasibility of this idea and if keen, perhaps suggest good sources for components ?
2. Per-unit meter systems aren't practical here as peak demand is the real problem. Demand meters seem to be more expensive than normal meters, and being designed for the first world, most actually use quite alot of power or are not very good in low-power scenarios.
I'm attracted to the simplicity of clip-on household power meters like -http://www.electrisave.co.uk/ - that have clearly borrowed components from conventional probes and 'consumerised' them. In parallel with the system above these could be really useful. Does anyone know of an absolute bargain basement Chinese copy ?
Looking at a longer term product development route, or even combining existing bits ad-hoc, could the timing function on the PCB be hacked to control the relay mentioned above thus integrating the system.
3. Some villages have alot of unused, 'off-peak' electricity during the day. Many villagers also have 12V car batteries at home. I'd like to wire-in a charger/inverter unit to charge and regulate the battery and then, if possible, could the user draw power from the inverter and the grid simultaneously to double capacity for a limited period ? This would allow them to use a 1000W iron or boil a kettle without going over their household limit.
If anyone could advise me on a very cheap charger/inverter (roughly 500W) and again advise on the feasibility of this concept. Using back-up and grid power concurrently is a topic I can't find anything on ...
Huge thanks in advance for any help you can provide,
If I'm reinventing the wheel anywhere here, please let me know.
Cheers,
Morgan.
I don't have an electrical background (mechanical engineer) though currently find myself in Sri Lanka, working for a local NGO on off-grid electricity projects for the rural poor, and could really use your help.
Small, village-run micro-hyro plants of around 10-20kW are a mature solution here for getting power to isollated mountain communities. They provide between 100-400W peak power, per household, via a simple mini-grid. While 10 years ago when these projects began, villagers were happy to recieve this humble amount of power, their aspirations have grown. Now, the use of power-hungry western appliances is causing friction due to the lack of available capacity for all.
My main focus is to look technically and socially at the best ways to distribute what power there is fairly. At present there are no meters and a flat monthly tariff. Simplicity, reliability and minimal-cost are the key drivers as I'm sure you can guess.
If I get any response on this I should maybe split my ideas into different posts but for now I'll just go through them:
1. Working with the exisiting (very simple) household fuse-box, I'd like to wire in a 24 hr timer that runs on scavenged power (very low consumption) and that has battery backup, as power cuts are common. This clock (manual or digital whatever is cheapest) will be programmed to switch a relay or contactor that will re-route mains power from a 200W circuit breaker through a 700W circuit to correspond with peak (evening) and off peak (daytime) power capacity. The idea is to bar overuse of the agreed household power allocation.
Honesty is an issue, so the clock will be simply secured, though I'd like the family to be able to reset the circuit breakers if overuse is accidental. The village prefer fuses ... Does anyone know whether circuit breakers can be manually overridden or not ? (provided they cannot be removed).
Can anyone advise me on the technical feasibility of this idea and if keen, perhaps suggest good sources for components ?
2. Per-unit meter systems aren't practical here as peak demand is the real problem. Demand meters seem to be more expensive than normal meters, and being designed for the first world, most actually use quite alot of power or are not very good in low-power scenarios.
I'm attracted to the simplicity of clip-on household power meters like -http://www.electrisave.co.uk/ - that have clearly borrowed components from conventional probes and 'consumerised' them. In parallel with the system above these could be really useful. Does anyone know of an absolute bargain basement Chinese copy ?
Looking at a longer term product development route, or even combining existing bits ad-hoc, could the timing function on the PCB be hacked to control the relay mentioned above thus integrating the system.
3. Some villages have alot of unused, 'off-peak' electricity during the day. Many villagers also have 12V car batteries at home. I'd like to wire-in a charger/inverter unit to charge and regulate the battery and then, if possible, could the user draw power from the inverter and the grid simultaneously to double capacity for a limited period ? This would allow them to use a 1000W iron or boil a kettle without going over their household limit.
If anyone could advise me on a very cheap charger/inverter (roughly 500W) and again advise on the feasibility of this concept. Using back-up and grid power concurrently is a topic I can't find anything on ...
Huge thanks in advance for any help you can provide,
If I'm reinventing the wheel anywhere here, please let me know.
Cheers,
Morgan.
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