Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Energy efficient production of ornamentals - HH1330SPC

Energy efficient production is of increasing importance to growers and this research will aid their ability to meet the Government's declared intention to reduce COZ emissions and the challenges posed by the Climate Change Levy. Temperature averaging has great potential for energy saving in ornamental crops, particularly when associated with the use of thermal screens used at night. Screens would allow higher than usual night temperatures to be run to compensate for lower than usual day temperatures. This approach assumes that cropping rate is regulated by average temperature and the project will aim to determine (at Wellesbourne) whether this is the case for two representative ornamental species, petunia and impatiens. Research will also determine the effects of temperature averaging during the day when night temperature is held constant. It will also aim to determine the temperature range over which averaging can be carried out safely, and the maximum period over which averaging can be carried out without compromising final quality or timing. The effects of day temperatures on net photosynthesis, and interactions of temperature with light and COZ concentration will be determined (at Wellesbourne) and used to predict quality implications of averaging regimes. Greenhouse energy balance models will be modified (at Silsoe) to take account of temperatures varying within the day, varying between day and night, and the presence of thermal screens. These revised models will then be used to determine potential energy savings for a range of averaging regimes at different times of year. Simulation in year 3 will concentrate on energy efficiency analysis when CHP micro-turbines are installed. These physiological and energy balance studies will provide underpinning data to enable trials in year 3 to test averaging strategies based on either outside air temperature and / or solar irradiance. Benefits of the 'speaking plant' approach to glasshouse control will be assessed, as will its potential as an aid to energy saving.
1. To establish the flowering and growth responses of two representative ornamental species to average temperature achieved in various ways.
2. To model the photosynthetic responses of the two species, relating net photosynthesis to temperature, light and CO2, as a basis for predicting quality in contrasting temperature regimes.
3. To quantify glasshouse energy usage in contrasting energy-saving regimes by simulation using modified energy balance models, and to conduct an energy efficiency analysis when CHP is installed.
4. To devise and test optimized temperature averaging regimes under glasshouse conditions.
5. To test the potential of the 'speaking plant' approach (where glasshouse control is determined by plant temperature) as an integral element in energy saving strategies.
Project Documents
• Final Report : Energy efficient production of ornamentals   (1037k)
Time-Scale and Cost
From: 2000

To: 2003

Cost: £341,923
Contractor / Funded Organisations
Horticulture Research International
Energy Efficiency              
Natural Resources and Labour              
Fields of Study