Source
https://ir.canterbury.ac.nz/handle/10092/11588 — original source (opens in a new tab; the file is not redistributed)
CAENZ — Improving Dairy Shed Energy Efficiency (2007)
NZ primary for the dairy-shed electrical load — the load-breakdown source for the community-dairy energy leg
CAENZ’s instrumented study of five Southland dairy sheds (2005/06 and 2006/07 seasons), commissioned by Venture Southland and funded by the Sustainable Farming Fund and Dairy InSight. Headline: a typical shed uses about 100,000 kWh/yr, split water heating 29% · milk cooling 20% · vacuum pumping 17% · pumping/lighting/other 34% (Fig 2.1). It also gives per-process energy intensities (0.1 kWh/L water heating; ~860 kWh/yr per 1 °C of extra pre-cooling; ~2,850 kWh/yr from vat insulation; COP 2.7–2.9 for a healthy vat refrigeration unit). ⚠ These are commercial twice-a-day sheds handling ~15,000 L/day. The figures must be scaled down for a community micro-dairy (a few house cows), not applied raw — see NI relevance.
Summary
Improving Dairy Shed Energy Efficiency is a 122-page technical report by the New Zealand Centre for Advanced Engineering (CAENZ; authors Ken Morison, Warren Gregory, Rowan Hooper), published October 2007. It reports continuous instrumented monitoring of electricity, temperatures and flows in five Southland dairy sheds across two seasons, then trials of specific efficiency measures (variable-speed vacuum, rotary-vane pumps, improved pre-cooling, vat insulation, alternative water heating). It is a first-hand NZ measurement study, not a synthesis.
For Neobiome it is the anchor source for the electrical-load side of the community-dairy pathway. Nothing else in corpus breaks down where a dairy shed’s electricity actually goes, or gives the per-process intensities needed to size a milk-cooling and cleaning load. It complements the production side (OT_172 milkfat/cow, OT_171 feed demand) and the effluent-energy side (LIT_086 dairy anaerobic digestion), supplying the missing electrical-demand leg.
Key claims
- claim: "A typical Southland dairy shed uses about 100,000 kWh of electricity per year. Figure 2.1 distributes this as: water heating 29,000 kWh (29%); milk cooling 20,000 kWh (20%); vacuum pumping 17,000 kWh (17%); pumping, lighting & other 34,000 kWh (34%). [verified verbatim against the source]"
source_location: "Section 2.2 'Energy use in a dairy shed', Figure 2.1 'Distribution of 100,000 kWh annual energy use in a typical dairy shed', PDF p.17 (printed Page 7)."
- claim: "Daily energy flows (Fig 2.2): incoming electricity about 370 kWh/day; water heaters 105 kWh/day to heat 1,000 litres from 10 to 85 degrees C; vacuum pump 60 kWh/day; milk-vat chiller 80 kWh/day to cool 15,000 litres from 20 to 6 degrees C. [verified verbatim against the source]"
source_location: "Figure 2.2 'Energy flows and some water flows on a daily basis', PDF p.17 (printed Page 7)."
- claim: "Heating water for plant and vat cleaning from 10 to 85 degrees C costs about 0.1 kWh per litre in a conventional electric water heater. A typical shed uses about 1,000 L hot water per day (500 L to wash the vat + 500 L to wash the lines), rising to about 1,500 L/day if hot washes are used after every milking. Over a 270-day season, heating 1,000 L/day theoretically requires about 24,000 kWh, rising to about 29,000 kWh (about 29% of annual use) once cylinder and pipework heat losses are included. [verified verbatim against the source]"
source_location: "Section 2.2 (water heating, PDF p.17, printed Page 7) and Section 4 'Reducing Hot Water Use & Improving System Efficiency' (0.1 kWh/L; 500+500 L split), PDF p.41 (printed Page 31)."
- claim: "On a farm producing 15,000 litres of milk per day at peak season the refrigeration unit operates at a power of about 10 kW and typically runs about 10 hours per day at peak, consuming about 100 kWh of electrical energy per day; over a full season energy use is likely to be about 20,000 kWh, roughly 20% of the shed's total electricity. [verified verbatim against the source]"
source_location: "Section 6 'Milk cooling', PDF p.73 (printed Page 63); the 20% share also stated in Section 2.2, PDF p.18."
- claim: "Replacing a water-ring vacuum pump with a rotary-vane pump cut average daily energy use from 72 kWh/day to 45 kWh/day (Table 3.5), a saving of about 6,750 kWh/year (38%) for a 38-a-side herringbone shed (Graejo), worth about $945/year at 14 c/kWh. [verified verbatim against the source]"
source_location: "Section 3 'Vacuum Pumping', Table 3.5 'Comparison of energy use for the water ring and rotary vane vacuum pumps' (72 to 45 kWh/day, PDF p.29, printed Page 19); the 6,750 kWh/yr (38%) saving stated PDF p.28 (printed Page 18)."
- claim: "Vat refrigeration coefficient of performance (COP): the Patton CCH1200 air-cooled condensing unit has a catalogue COP in the range 2.7 to 2.9 at evaporating temperatures of -5 to 5 degrees C (Table 6.2). Measured in the trials (Table 6.3): the Graejo unit averaged COP 2.7 (range 2.0-3.8), but both Coldstream units performed below 2 - west 1.86, east 1.55 (ranges 1.6-2.1 and 1.4-1.7). A poorly performing unit therefore roughly halves cooling efficiency versus a healthy one. [verified verbatim against the source]"
source_location: "Section 6.3 refrigeration, Table 6.2 'Expected performance of a Patton Refrigeration CCH1200' (catalogue COP 2.7-2.9, PDF p.80) and Table 6.3 'Typical performance of Graejo and Coldstream refrigeration systems' (Graejo 2.7; Coldstream west 1.86, east 1.55, both below 2; PDF p.81)."
- claim: "Every 1 degree C reduction in the milk temperature leaving the pre-cooler (plate cooler) saves about 860 kWh/year (about $120/year at 14 c/kWh) in vat refrigeration. [verified verbatim against the source]"
source_location: "Section 6 'Milk cooling', pre-cooler analysis, PDF p.79 (printed Page 69): 'Every 1 degree C drop ... about $120 (860 kWh) per year'."
- claim: "An insulating wrap fitted to the milk vat reduced heat gain into the milk by about 80% (measured on comparable-weather days). The estimated annual reduction in heat gain (about 5,700 kWh/year of heat) corresponds to about 2,850 kWh/year of electricity saved, worth about $400/year at $0.14/kWh; the wrap cost about $2,800 installed. [verified verbatim against the source]"
source_location: "Section 6.4 'Milk Vat Insulation', PDF p.81-82 (Polar Wrap ~$2,800 installed; heat gain 80% less for the insulated vat; ~5,700 kWh/yr heat = ~2,850 kWh/yr electricity)."
- claim: "The report is based on continuous instrumented monitoring of five Southland dairy sheds over the 2005/06 and 2006/07 seasons: Coldstream Downs (Riversdale, 60-bail rotary, 800 cows), Glencairn Land Company (Dipton, 50-bail rotary, 680), Graejo Trust (Thornbury, 38-a-side herringbone, 670), Moorabool Farm (Dipton, 40-a-side herringbone, 600) and Tussock Creek Dairies (Winton, 50-bail rotary, 750). Annual electricity cost for a typical farm was $12,000-$16,000 at 12-16 c/kWh (April 2007). Spray irrigation of pasture was excluded from scope. [verified verbatim against the source]"
source_location: "Section 2.3 'Instrumentation and Measurement', Table 2.1 (PDF p.19, printed Page 9); electricity cost and irrigation-exclusion in Section 2.2 (PDF p.17)."Neobiome Intelligence relevance
Feeds [d01_renewable_energy_storage] as the dairy-shed electrical-load item for the community energy model — the demand-side counterpart to the production and effluent legs of the community-dairy pathway. It sits alongside the other cross-cutting NZ energy-demand primaries (RD_007, OT_028, RD_008); the same source also informs the food/dairy pathway (kWh load ↔ community dairy).
What it supplies that nothing else in corpus does:
| Term | Value (PDF page) | Use |
|---|---|---|
| Whole-shed load split | water heating 29% / milk cooling 20% / vacuum 17% / other 34% (p.17) | apportion a dairy load into its drivers |
| Water-heating intensity | 0.1 kWh/L, 10 to 85 degrees C (p.41) | scales directly with hot-water volume |
| Pre-cool sensitivity | ~860 kWh/yr per 1 degree C off the pre-cooler (p.79) | value of better plate-cooling / cold water |
| Vat-insulation saving | ~2,850 kWh/yr, ~80% heat-gain cut (p.82) | fixed retrofit saving |
| Refrigeration COP | 2.7-2.9 healthy, <2 when poor (p.80-81) | electricity per unit heat removed |
Carry these caveats into any use of the absolute figures:
- Scale. Every headline number is for a commercial twice-a-day shed handling ~15,000 L/day. A community micro-dairy (a handful of house cows, tens of litres/day) will not scale linearly: volume-driven loads (water heating at 0.1 kWh/L, cooling at ~1 kWh per degree per unit volume) shrink with throughput, but fixed loads (vacuum, lighting, standby refrigeration) do not, so the kWh-per-litre intensity rises sharply at small scale. Use the per-process intensities, not the 100,000 kWh/yr total, to size a community system.
- No engine cell is auto-changed by this ingest. It establishes the load structure and intensities; wiring them into a sized community-dairy load is a modelling step, not a data entry.
- Vintage. 2007 measurements. Vacuum and refrigeration efficiency benchmarks may have improved with newer equipment (e.g. variable-speed drives are now standard), so treat the “poor unit” cases as a floor, not today’s norm.
Notes
- Authoritative NZ primary, downloaded. 122 pp.
data_quality: verified. The live University of Canterbury repository URL returned a Cloudflare 403; the byte-identical original October-2007 CAENZ PDF was retrieved from the Wayback Machine (content = the original repository file). Commissioned by Venture Southland; funded by the Sustainable Farming Fund (MAF) and Dairy InSight; authored by CAENZ. - Page numbering: PDF page = printed page + 10 (about 10 pages of front matter). Citations above give the PDF page, with the printed page noted where confirmed.
- Corrections to figures carried by the compiled research. (a) The load split is vacuum 17% / other 34% from the Fig 2.1 pie chart, NOT the compiled research’s “16% / 35%” — the 16% is a separate in-text worked example (a 10 kW pump running 1,600 h/yr = 16,000 kWh ≈ 16%), while the headline chart rounds to 17,000 kWh (17%). (b) Vacuum daily use is 72 to 45 kWh/day (Table 3.5), NOT the compiled research’s “71 to 44”; the 38% reduction and 6,750 kWh/yr are exact in both.
- Precision on the poorly performing refrigeration units. The “one poor unit COP 1.7” figure sometimes quoted is imprecise: the two measured poor units averaged COP 1.86 (Coldstream west) and 1.55 (east), both below 2; 1.7 is only the top of the east unit’s 1.4-1.7 range. The claim records the measured averages.
- Distinct from the dairy-stats (OT_172) and dairy-AD (LIT_086) pages; it is the only CAENZ / dairy-shed-energy measurement source in the corpus.
Research targets
Documents to retrieve
- None. Dairy-shed electrical load is now well-sourced by this primary alongside the Massey dairy-shed power-systems thesis.
Research gaps
- Recorded, not raised as a target: a community-/house-cow-scale electrical load figure (versus these commercial ~15,000 L/day sheds). This is a scaling-model task built from the per-process intensities above, not a retrieval target.
Connections
Links to
Referenced by
EDT domains (1): D01: Renewable Energy & Storage Systems
Sources (1): CR_057