Energy Usage Investigation and Evaluation of a Brewery By Nadia McPherson Supervisors: Dr Yaodong Wang, Professor Tony Roskilly, Dr Barbara Sturm
Energy Usage Investigation and Evaluation of a Brewery
By Nadia McPherson
Supervisors: Dr Yaodong Wang, Professor Tony Roskilly, Dr Barbara Sturm
Outline
• Aims and Objectives
• Summary of literature review
• Introduction to a brewery
• Methodology
• Results
• Discussion & Conclusion
• Limitations & Future Work
Aims & Objectives
• Reduce it’s reliance on fossil fuels.
• Reduce costs and promote sustainable image.
• In order to achieve this: – Energy Audit: Evaluate total energy consumption
– Calculate theoretical energy requirement
– Identify possible waste
– Recommendations of work to be completed
– Evaluate solar resource
– Design solar electricity system
IMechE Energy Hierarchy
[1]
Literature Review Findings • Energy Audit:
“An examination of an energy consuming equipment/system to
ensure the energy is being used efficiently” [2]
• Energy savings of up to 60 % [3]
• Steps of an Energy Audit: Collect building information Identify characteristics of energy consuming equipments Site surveys & metering records Analyse past energy bills Seasonal variation of the load
Calculate the EUI Comparison of EUI with best practise guidelines Identify potential EMO’s Quantify the energy savings Evaluate the economics of each EMO
Literature review findings
• 3 – 8 % of costs [3]
• Energy consumption: – Brew house 64 %
– Wort boiling
– Cooling & Machine drive 78 %
– Varies with breweries
[3]
Literature Review Findings
• Energy Management Opportunities (EMO): – Waste heat recovery
• Vapour condenser, Vapour compression, Heat exchanger, Boiler flue gases
– Pinch Analysis [3]
“linking of the hot and cold streams of a process in a thermodynamically optimal way and matches the
components in size, function and capability”
– Boiler maintenance & optimisation
The Brewery
• Micro-brewery
• Producing 56,000 litres per month
• Refurbished in 2006
• 500 mm thick sandstone
• Pitched slate roof
• 100 mm polystyrene insulation
• False ceilings
• 50 mm rock wool insulation
Actual Energy Consumption
Electricity bill
Oil bill
Theoretical energy consumption
Purely Electrical
• Pumps A – C : Each rated at 0.75 kW
• Boiler Blower: 240 V & 14.9 A (From specifications)
• Lighting and office equipment
• Total electricity consumed: – Average: 94 kWh per day
– Maximum: 102 kWh per day
• Greatest consumer: Computers
Electricity for heating & cooling
• All process chilling & room heating & cooling
• CLT, FVs, Brew hall, Cold room, Refrigeration room
• Total electricity chillers (kWh per day): – 25 (Max), 19 (Ave), 13 (Min)
• Total electricity ACs (kWh per day): – 28 (Max), 3 (Ave), 2 (Min)
• Total electricity heating (kWh per day): – 19 (Max), 45 (Ave), 91 (Min)
Thermal energy
• Hot Liquor Tank (HLT) and Copper Tank (CT).
• Total thermal energy HLT (kWh per day): – 243 (Max), 97 (Ave)
• Total thermal energy CT (kWh per day): – 214 (Ave)
• As expected, wort boiling is greatest demand.
Discussion
Discussion of results
• Actual cooling capacity: 568 KWh per day
– Theoretically only require 183 kWh per day
• Actual electricity consumption of HVAC & Chillers – 103 kWh per day (Chillers & heater) 43 %
– 169 kWh per day (Chillers & ACs) 70 %
• Significantly less heating & more cooling
• Inefficiencies
Discussion of results
• According to oil bill data: 131 KW 66 %
• Theoretical and actual boiler comparison: – Average: 211 % of theoretical
• Heat loss from processes
• Significant energy saving potential
• Especially in optimisation of the thermal energy
Comparison with benchmarks
• Calculate EUI
• Utilising historical bill data
• Benchmarks [4]: – Thermal: 23.6 – 33 kWh per hectolitre
– Electrical: 7.5 – 11.5 kWh per hectolitre
• Most potential for savings in electrical
• Thermal energy within BAT guidelines
• Conflicting results
System recommendations
System recommendations • HLT
– Ill-fitting lid
– Moisture problem within brew hall
– Recover waste heat using vapour condenser
– Process hot water or space heating
• Wort boiling – Largest thermal energy demand
– Recover heat using thermal vapour compression
– Water at around 108 °C
– Used to pre-heat wort
System recommendations
• Layout: – Cold room:
• Air movement between cold room & brew hall
• Solution 1: Create alternative route to brew hall
• Solution 2: PVC curtains on the doors
– Brew hall:
• Houses HLT, MT, CT, Boiler Process heat
• 34 °C recorded during copper boiling
• Solution: Move the FVs into separate room
• Thermostat ventilation system to utilise heat
System recommendations • Insulation of stone walls
– U-Value 2.1 Wm-2K-1
– Internal vs external
– Phenolic insulation 10 % of U-Value
• Wet rock wool insulation – False ceilings 50 mm insulation
– 0 % moisture assumed for calculations
– Water filtrates into air gaps
– 20 % moisture thermal conductivity 0.1 Wm-1K-1 [5]
– 9 kWh to 19 kWh (Brew hall)
Solar design
• System description: – Location is 54 °N
– Available roof space: 650 m2
– Orientation: South-West
– Two scenarios: 10 kW and 20 KW
– Grid-connected
– Module selected: Yingli YL 210 P-26b
Solar design
• Expected generation: – 10 kW: 7.85 MWh per year (8.9 %)
– 20 kW: 15.68 MWh per year (17.7 %)
• Costing: – 10 KW: £34,606
– 20 KW: £55,342
Conclusions
Conclusions
• Significant potential for energy savings – Electricity: 153 % of theoretical
– Thermal: 211 % of theoretical
• System should be optimised: – Waste heat recovery in the HLT & CT
– Moisture in insulation
– Current layout
• Then, consider solar electricity.
Future work & Limitations
• Limitations: – Inaccuracy of data provided (temperatures etc)
– Lack of recorded data
• Future work: – Establish accurate measurements of all parameters
– Financial cost & benefit of each system recommendation
Citations
• [1] IMechE. (2009) The Energy Hierarchy.
• [2] European Commission. (2005) 'The European greenbuilding programme energy audit guidelines', [Online].
• [3] Galitsky, C., Martin, N., Worrell, E. and Lehman, B. (2003) Energy efficiency improvement and cost saving opportunities for Breweries. California: Energy Star.
• [4] Scheller, D. L., Michel, D. R. and Funk, U. (2008) 'Efficient use of energy in the brewhouse', Master Brewers Association of America, 45, (3), pp. 263-267.
• [5] Powell, F. J. and Matthews, S. L. (1987) Thermal Insulation: Materials and Systems. ASTM committee C-16 on thermal insulation: Baltimore.
Acknowledgments
• Dr Yaodong Wang
• Barbara Sturm
• John Boyle
• Matthew Butcher
• Robert McKeon
• Ian Milne, Sharon Joyce
Thank you for listening.
Any questions?