Feasibility study of a geothermal application for a small brewing plant

Client: Azienda Agricola Mirri Piana s.s.
Location: Castel San Pietro Terme (BO), Italy
Date: 2016

The study is aimed to assess the feasibility of geothermal energy systems for satisfying the thermal energy demand of a small brewing plant.

Project Goals

  • Renewable energy supply for brewing plant thermal loads
  • Finding the best geothermal application from the technical-economic point of view

Activities Performed

  1. Gathering of hydrogeological and temperature data of the area;
  2. Analysis of the thermal loads (heating and cooling) needed for the brewing process;
  3. Preliminary design of different geothermal systems;
  4. Preliminary economic analysis of the different solutions.

Technical data

Operating mode: chilling, heating & cooling
Solution analysed: hybrid solution coupling geothermal / air heat pumps
Chilling power: 7.5 kWt
Heating & cooling power: 6 kWt
Brewing process phases considered: fermentation, maturation, offices heating and cooling
Phases working temperatures: fermentation +3°C, maturation -5°C, H&C +20°C

Technical feasibility

The feasibility study led to the design of a non conventional heating/cooling system using ground source heat pump coupled with air heat pumps, and to the identification of the best solution from a technical and economic point of view.
The use of in-house developed software allowed for a proper geoexchange system design.
The analysis of different technological solutions provided detailed information about projects with different investment costs and return periods.

Winter functioning of the combined system

Summer functioning of the combined system

Geoexchange system with borehole heat exchangers (BHE)

 

  • Number of wells: 4
  • Spacing (m): 8
  • Depth (m): 100

 

 

Geoexchange system with open loop application

 

  • Number of wells: 1
  • Depth (m): 100

 

 

Geoexchange system with geothermal spirals

 

  • Number of spirals: 15
  • Spacing (m): 4
  • Depth (m): 3
  • Diameter (m): 0.4

 

Geoexchange system with geothermal baskets

 

 

  • Number of baskets: 8
  • Spacing (m): 4
  • Depth (m): 2
  • Diameter (m): 1.9

 Economic Feasibility

The different geothermal solutions were compared with an air heat pump alternative solution and the break even point was found.

Type of geothermal solution Investment (€) Break even point (y)
Open loop 45.500 ~16
Closed loop 35.100 >20
Spirals 17.400 10
Baskets 20.200 ~15

 

Economical analysis for the best solution (spirals) compared to the full air heat pump one