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?