Ditch the Batteries: Off-Grid Compressed Air Energy Storage. Compressed Air Energy Storage (CAES) is usually regarded as a form of large-scale energy storage, comparable to a pumped hydropower plant. Such a CAES plant compresses air and stores it in an underground cavern, recovering the energy by expanding (or decompressing) the air through a turbine, which runs a generator. Unfortunately, large-scale CAES plants are very energy inefficient. Compressing and decompressing air introduces energy losses, resulting in an electric-to-electric efficiency of only 40-52%, compared to 70-85% for pumped hydropower plants, and 70-90% for chemical batteries. The low efficiency is mainly since air heats up during compression.
Why Small-scale CAES? In the previous article, we outlined several ideas – inspired by historical systems – that could improve the efficiency of large-scale CAES plants. The main reason to investigate decentralised compressed air energy storage is the simple fact that such a system could be installed anywhere, just like chemical batteries. Sans titre. Sans titre. There is an immediate objection; transmitting power by compressed air is horribly inefficent, because all the heat created in the compressor is lost long before the air gets to the point of use. Nonetheless the Paris network flourished for many years. Factory-wide compressed air networks for driving power tools are commonplace, but only Paris had a city-wide network. The roots of the system go back to 1879 when the Austrian engineer Viktor Popp set up the Compagnie des Horloges Pneumatiques (CGHP)to drive pneumatic public clocks with one air pulse per minute, after authorization to install a compressed air network was granted by the City of Paris.
At the time compressed air was in the air, so to speak, following the extensive use of compressed air for rock drilling in the construction of the Mont Cenis tunnel, which was initially expected to take 25 years but was opened in 1871 after only 14 years following the introduction of pneumatic equipment. Sans titre. Sans titre. Water pump operated by small air compressor turned with windmill blades This is a simple little pump with only 3 moving parts.
A piston, piston return spring and exhaust piston/valve. The theory of operation is very simple. A small air compressor such as you get a any 'large-mart' that runs on 12 volts from your battery is dissassembled and the little electric motor exchanged for windmill blades. It is then mounted on a frame and put on the top of a pole!. The small air compressors are generally rated as much as 250 psi but that will not be needed here. The pump is actually capable of working with the full output pressure of the compressor and pump water pretty high up if needed though - the pump would have to be built out of all metal for reliability though I think in that case... 1) The air from the compressor is fed on top of the piston forcing it down and pumping the water out. 4) The piston return spring to raises the piston back up refilling the pump casing with water.
Windmill with air compressor instead of electric generator (wind forum at permies) Bill Bianchi wrote:I've been looking into steam engines and gasifiers. They work to charge a battery bank, but it takes 4-6 hours and you need to actively run the engine as the batteries charge. (Batteries can accept only so much energy each hour without damaging them) So, I thought of using these engines to compress air. It wouldn't take more than an hour to fill a big air tank with an engine-powered compressor, would it? That doesn't seem too bad a run time for a steam engine or gasifier. The air would run a pneumatic motor, which would run a generator that charges a battery bank. Couldn't I start the pneumatic motor and walk away while it charges the batteries?
My thoughts are that having to maintain and generate (i.e. convert) energy through additional components would raise costs and lower efficiencies. A wood gasifier can be devised to operate at low power levels for extended periods, but there has not been good success here on anything but charcoal fuel. Sans titre. The major challenge in integrating wind energy into the electrical grid is that the resource is intermittent and unpredictable so that energy is always available. With an energy storage system integrated with a wind turbine, surplus energy can be stored and then regenerated when demand is higher.
In the proposed Compressed Air Energy Storage (CAES) system (graphics 1) energy is stored prior to electricity generation, eliminating the need and losses associated with generating electricity twice. This also allows the electrical generator and transmission lines to be downsized for mean power instead of peak power. This can be a significant cost-saving for off-shore installations as their capacities are currently under-utilized by over 50%. Further savings comes from replacing a failure prone mechanical gearbox in the nacelle with a hydraulic pump, and installing the rest at the ground/sea level. Our system has two key innovations compared to a conventional CAES. Blog Archive » Solving the flexible biogas digester problems. You’d think that given the amount of cow dung available around rural Africa that biogas would be a big hit right?
Well, its actually relatively unknown. The main reason is materials, coast and complicated technology. People in these areas use charcoal or wood for their domestic cooking needs – its not only dirty hard work to collect firewood, but it’s unhealthy and damages the environment. But, it’s free … We believe that biogas from cow dung holds huge promise for rural and urban areas as a cheap source of energy that can be turned into domestic use or even business anywhere in rural Kenya….eg. pasturizing milk, making yoghurt, running fridges, generators, hammer mills for grinding corn, cooking, baking, heating water, running machines… and reducing your carbon footprint.
I have recently become the latest guinea pig for Dominic Wanjihias experiments … and it has been quite a learning experience Biogas system on a motorbike in Kenya You may need a Dominic to help set it up Problem No. 2.