HP State Cooperative Milk Production Federation

General Information
Description of the company

HP Dairy State Co-operative has several milk plants across the state. The Duttnagar milk plant in Tehsil-Rampur Bushar, District Shimla, was built in 2011 and has a staff size of about 50 personnel. Between 34,000 and 40,000 litre milk are processed per day. Beside fresh milk products about half of the milk is processed to milk powder.

Type of Industry


Location of the company

The solar system is installed on the roof of the milk plant at:
HP Mild Fed. Ltd.,
Milk Plant Duttanagar, Tehsil,
Rampur Busha, District Simla,
Himachal Pradesh.

Heat demanding processes

Steam is used for pasteurization, cream separation, hot water jackets for ghee production, butter making, in curd preparation, paneer preparation and evaporation in powder plant.

Conventional heat supply

A steam boiler with 2.5 TPH steam capacity generates steam at 110°C at a pressure of 6 to 7 kg/cm2.
(TPH = tons per hour)

Conventional fuel used

Hight speed diesel (HSD) is used at the steam boiler, which costs about Rs. 57.5 per litre. On an average 700 litres of HSD is used per day in the boiler. This accounts to 255,500 litres of HSD per year considering 365 days of plant operation.

Motivation to use solar thermal energy

The increase in the fuel prices has motivated the management to go for other non-conventional applications of solar energy.



Description of the solar thermal system

  • Non-pressurized FPC solar water heater plant for preheating of steam boiler feeding water. The SWHS is designed to deliver about 6000 LPD hot water with 60OC. (FPC = flat plate collector, LPD = litre per day)

  • The SHIP was commissioned in 2013.

  • The SWHS has 60 FPC panels with selective coating of 2 X 1 m size with a total gross area of 120 m2. The panels are installed over the flat roof of the plant. There are 5 collector fields connected in parallel. The collector field is oriented towards south-east.

  • The water storage tank has a volume of 6000 litre. It is insulated with rock wool of 100 mm thickness and protected by an aluminium cladding.

  • The insulated water storage tank is of 6000 LPD capacity made of SS 304. It is insulated with a 48kg/m2 rock wool of 100 mm thickness and an aluminium cladding.

  • Hydralic scheme of the solar water heating system at Himachal Pradesh Dairy Milk plant Duttnagar, Tehsil-Rampur Bushar, District Shimla

  • The solar system was designed, delivered and commissioned by:
    KotakUrja Pvt Ltd
    No.378,10th Cross,4th Phase,
    Peenya Industrial Estate,Bangalore

  • The plant maintains records for the HSD consumption each day.

Energy balance

  • In the average about 700 litre high speed diesel (HSD) is used per day or 250,000 litre per year. This corresponds to an energy demand of 5.5 Mio kcal or 6.4 MWh per day and 1990 kcal or 2300 MWh per year. (Assumptions on HSD: Gross caloric value of 11,000 kcal/kg, density 0.71 kg/litre)

  • The site receives an annual solar irradiation between 3.4 to 5.0 kWh/m2 per day.

  • Will be calculated based on monitoring results

  • Will be calculated based on monitoring results

  • Will be calculated based on monitoring results

  • Will be calculated based on monitoring results


  • Investment costs of collector fields: INR 1.086 Mio (EUR 13,600) and for the 6000 litre storage tank: INR 0.581 Mio (EUR 7,300). Total investment costs: INR 1.667 Mio (EUR 20.800).
    This corresponds to total investment costs of INR 14,000 (EUR 175) per m2 collector area.

  • MNRE grant are INR 13,200 (EUR 165) per collector, which corresponds to INR 792,000 (EUR 9900) or 47.5% of total costs.

  • The payback period is calculated as: Payback period [years] = Net investment costs of owner [INR] / annual savings [INR/year] The calculation will be based on the monitoring results


  • The system has been functioning well.

  • Rakesh Kumar Chauhan (Production Manager): "I am very satisfied with the solar hot water system, the temperature of the collector field reaches typically 60°C as expected."

  • The manufacturer has also indicated that the plant has been functioning to their satisfaction.