icebank
NSL on Rural Delivery - TVNZ Interview
Ian and Malcolm were interviewed by Rural Delivery, a TVNZ Saturday morning presentation.
Rural Delivery TV Interview
Rural Delivery TV Interview
Sorting the Brass from the Muck
Ian Bywater’s work on energy savings in dairy farming.
In 2003, SEF member Ian Bywater won the New Spirit Challenge award, offered by the UK Institution of Electrical Engineers for an engineering project that promotes sustainability. Entries must show multidisciplinary thinking and imagination as well as novelty, and offer potential opportunities for the engineering community.
The latest news is that research on the main components of the system is complete and application has been made for grants to fund a demonstration plant for a dairy herd of 200 cows.
The problem Many network companies are experiencing a growing electrical load on rural networks, due to the rapid increase in dairying in New Zealand. In addition to the general problem of increasing demand, there are undesirable morning and evening system peaks caused by the refrigeration load. The total load can strain long rural power systems that are often not designed for such loadings.
capacity if the network supply fails.
•A biodigester to treat the dairy shed effluent, providing a primary source of energy. Initial trials
will have electrical backup, but LPG is another option if only occasional backup is needed.
•A Stirling engine to generate power from biogas.
•Solar thermal heating for shed hot water.
•Local groundwater for initial milk cooling, if available.
•Further integration, such as using biogas or waste heat from the Stirling engine to heat water for shed use, and hot water to maintain the biodigester at optimum temperature.
The potential benefits of such as system include reduced electrical energy use; further reductions in peak electrical energy use; improved effluent disposal; reduced methane emissions; and reduced investment in rural power supplies.
The award judges envisaged several stages in project development, provided that each preceding stage is a success:
•Undertake a desktop study into the energy balance of the system.
•Undertake a world-wide search of suitable suppliers of equipment.
•Formulate a system as described and seek research funding.
•Operate an ice bank for a number of daily cycles to determine its characteristics in a laboratory and report back the test results.
•Operate the digester for a number of weeks to determine its characteristics in a laboratory.
•Use the biogas produced to fuel a Stirling engine, and report back the test results.
•Combine the ice bank operation with the power output from the Stirling engine generator.
•In conjunction with a network company, locate a suitable dairy farm where the system will be
installed. This ‘on-farm’ situation will enable a comparison between operations with and without
the ice bank.
•Analyse and report on the results.
•Commercial development.
A herd of 200 cows producing 2000 l of milk at each milking requires a cooling capacity of 70 kWh, or 35 kW for two hours. For a typical refrigeration unit with a CoP of about 2–3 this requires about 12–18 kW of electrical compressor power.
The load can be reduced by using local ground water as a heat sink for the first stage of cooling, from say 37–25˚C. This will reduce the power requirement by about 40%, but at the expense of drawing about 2 l of water from the aquifer for each litre of milk cooled.
Using an ice-bank to store cooling capacity reduces the load, and also the size of refrigeration equipment, making it more environmentally beneficial. In this way the two-hour cooling requirement can be met from ice generated over a period of up to 12 hours. This will need a
refrigeration system only about 1/6 as large; 2–3 kW capacity for total cooling, or 1.5– 2.0 kW if used with water as an initial cooling agent. The amount of ice required is about 400 g/l of milk (latent heat of fusion 320 kJ/kg, specific heat of milk 4.2 kJ/lK, cooling range 30 K), or just under 800 kg for 2000 l.
For two-stage cooling the ice requirement is about 60% of this, or around 500 kg.
The operation of the ice-bank is as follows:
•During the ice making period the refrigeration system runs continuously at a capacity of 6 kW
(cooling) or about 2 kW (electrical). This load can be met by a Stirling engine running on biogas,
with LPG available as a back-up energy source.
•During the milk cooling period the ice is melted to produce water at 0˚C (or cooler if a lowered freezing-point fluid is used). This cools the milk to 7˚C, and in doing so, its temperature rises to say 2˚C. The ‘warm water’ is recycled to the ice-bank where it is re-cooled to 0˚C by melting more ice.
By the end of the milk-cooling period, all the ice has melted and all the milk has been cooled. The cycle begins again.
Hot water is also needed; very roughly 300 l /day at 85˚C. This typically uses a 6 kW electric heater, but some large farms use a 1200 l tank with a14 kW element (with permission from the retailer). In a more sustainable system, energy for water heating could come from a solar heater; waste heat from the Stirling engine; biogas; mains electricity; or LPG, in about that order of priority (but probably not all in the same installation!).
Clearly a fully integrated system is going to be fairly expensive and need some fairly sophisticated
controls, but with some very real benefits available.
This article is largely taken from the New Spirit Challenge award notice with additional information from Ian Bywater and Malcolm Souness
In 2003, SEF member Ian Bywater won the New Spirit Challenge award, offered by the UK Institution of Electrical Engineers for an engineering project that promotes sustainability. Entries must show multidisciplinary thinking and imagination as well as novelty, and offer potential opportunities for the engineering community.
The latest news is that research on the main components of the system is complete and application has been made for grants to fund a demonstration plant for a dairy herd of 200 cows.
The problem Many network companies are experiencing a growing electrical load on rural networks, due to the rapid increase in dairying in New Zealand. In addition to the general problem of increasing demand, there are undesirable morning and evening system peaks caused by the refrigeration load. The total load can strain long rural power systems that are often not designed for such loadings.
The proposal
•An ice bank to reduce the peak refrigeration load, by spreading it over 6–12 hours instead of a 2 hour milking period. Ice banks have other benefits to the dairy industry, such as reserve coolingcapacity if the network supply fails.
•A biodigester to treat the dairy shed effluent, providing a primary source of energy. Initial trials
will have electrical backup, but LPG is another option if only occasional backup is needed.
•A Stirling engine to generate power from biogas.
•Solar thermal heating for shed hot water.
•Local groundwater for initial milk cooling, if available.
•Further integration, such as using biogas or waste heat from the Stirling engine to heat water for shed use, and hot water to maintain the biodigester at optimum temperature.
The potential benefits of such as system include reduced electrical energy use; further reductions in peak electrical energy use; improved effluent disposal; reduced methane emissions; and reduced investment in rural power supplies.
The award judges envisaged several stages in project development, provided that each preceding stage is a success:
Stage 1
•Undertake a desktop study into the energy balance of the system.
•Undertake a world-wide search of suitable suppliers of equipment.
•Formulate a system as described and seek research funding.
Stage 2
•Operate an ice bank for a number of daily cycles to determine its characteristics in a laboratory and report back the test results.
•Operate the digester for a number of weeks to determine its characteristics in a laboratory.
•Use the biogas produced to fuel a Stirling engine, and report back the test results.
•Combine the ice bank operation with the power output from the Stirling engine generator.
Stage 3
•In conjunction with a network company, locate a suitable dairy farm where the system will be
installed. This ‘on-farm’ situation will enable a comparison between operations with and without
the ice bank.
•Analyse and report on the results.
Stage 4
•Commercial development.
The numbers
Dairy farms generally operate on a regular, twice-a-day milking pattern, although once-a-day is becoming more common and milk collection may be only every other day. The milk comes from the cow at about 37˚C and needs to be cooled to below 7˚C within two hours of milking.A herd of 200 cows producing 2000 l of milk at each milking requires a cooling capacity of 70 kWh, or 35 kW for two hours. For a typical refrigeration unit with a CoP of about 2–3 this requires about 12–18 kW of electrical compressor power.
The load can be reduced by using local ground water as a heat sink for the first stage of cooling, from say 37–25˚C. This will reduce the power requirement by about 40%, but at the expense of drawing about 2 l of water from the aquifer for each litre of milk cooled.
Using an ice-bank to store cooling capacity reduces the load, and also the size of refrigeration equipment, making it more environmentally beneficial. In this way the two-hour cooling requirement can be met from ice generated over a period of up to 12 hours. This will need a
refrigeration system only about 1/6 as large; 2–3 kW capacity for total cooling, or 1.5– 2.0 kW if used with water as an initial cooling agent. The amount of ice required is about 400 g/l of milk (latent heat of fusion 320 kJ/kg, specific heat of milk 4.2 kJ/lK, cooling range 30 K), or just under 800 kg for 2000 l.
For two-stage cooling the ice requirement is about 60% of this, or around 500 kg.
The operation of the ice-bank is as follows:
•During the ice making period the refrigeration system runs continuously at a capacity of 6 kW
(cooling) or about 2 kW (electrical). This load can be met by a Stirling engine running on biogas,
with LPG available as a back-up energy source.
•During the milk cooling period the ice is melted to produce water at 0˚C (or cooler if a lowered freezing-point fluid is used). This cools the milk to 7˚C, and in doing so, its temperature rises to say 2˚C. The ‘warm water’ is recycled to the ice-bank where it is re-cooled to 0˚C by melting more ice.
By the end of the milk-cooling period, all the ice has melted and all the milk has been cooled. The cycle begins again.
Hot water is also needed; very roughly 300 l /day at 85˚C. This typically uses a 6 kW electric heater, but some large farms use a 1200 l tank with a14 kW element (with permission from the retailer). In a more sustainable system, energy for water heating could come from a solar heater; waste heat from the Stirling engine; biogas; mains electricity; or LPG, in about that order of priority (but probably not all in the same installation!).
Clearly a fully integrated system is going to be fairly expensive and need some fairly sophisticated
controls, but with some very real benefits available.
This article is largely taken from the New Spirit Challenge award notice with additional information from Ian Bywater and Malcolm Souness
Biogas the New Power Source?
Biogas the New Power Source?
A Christchurch power engineer is developing technology that, in future, could see dairy sheds powered entirely by cow waste. Engenius Solutions’ Ian Bywater’s idea for asustainable system for cleaner dairying won the prestigious Institute of Electrical Engineers New Spirit Challenge Award, which rewards ideas for sustainability-oriented engineering projects, last year. Read More...
Energy : Effluent power goes high-tech
Energy : Effluent power goes high-tech
By Anne LeeA Christchurch company has begun a farm-scale trial of a system that can use effluent to make electricity, heat water and cool milk.
BioGenCool, produced by Natural Systems, is projected to cut around one third off the electricity bill for farm dairies. At the same time it will provide rapid and constant milk cooling, improve the quality of the effluent, reduce greenhouse gas emissions and reduce water use.
Landcorp Farming is about to trial the system on its 850-cow Waimakariri dairy farm near Christchurch. Read More...
Biomass to Cogeneration for NZ Dairy Farms
01/10/05 14:26 Filed in: Biogas | Energy Efficiency
Biomass to cogeneration for New Zealand dairy farms Dairy farms could form an ideal application for cogeneration plants fuelled by biogas produced on-site by the anaerobic digestion of manure. Such a solution would cut farmers’ electricity bills and help to solve a waste disposal problem, writes Ian Bywater... Read More...
Finding Power in Effluent
By TIM CRONSHAW - The Press | Friday, 29 August 2008
A dairying system that is turning effluent into power and fertiliser in Canterbury is expected to revolutionise the way farmers treat cow muck.
Its investors have set up a pilot plant at a Landcorp Farming dairy farm in Eyrewell that is extracting methane and carbon dioxide from effluent with biodigester technology, and using it as fuel in a co-generation plant to make electricity. Read More...
A dairying system that is turning effluent into power and fertiliser in Canterbury is expected to revolutionise the way farmers treat cow muck.
Its investors have set up a pilot plant at a Landcorp Farming dairy farm in Eyrewell that is extracting methane and carbon dioxide from effluent with biodigester technology, and using it as fuel in a co-generation plant to make electricity. Read More...