LAMP Lighting Calculators

This ‘How often will reach my targe DLI?’ calculator is like the LAMP ‘Unlimited’ Lighting Calculator’ (which you will find below) but it takes the opposite approach: users specify the capacity of their lighting system, and the calculator will estimate how many days of the year you can reach your target DLI. The associated electricity costs and demand charge are estimated as well. This calculator is particularly useful for determining how well an existing lighting system meets your needs. You can refer to our guidance document to see how the calculator works before using it. 
Guide – LAMP Target DLI Calculator 

With this calculator, users specify how many days of year they want to be able to reach the target DLI (expressed as a percentage of 365 days). When set to 100%, this calculator is essentially the same as the ‘Unlimited lighting calculator’. But typically, there is no need or desire to reach the target DLI every single day. After entering what % of days you want to reach the target DLI, the calculator will determine the  required lighting capacity and provide a graphical summary of the lighting conditions you can expect in your greenhouse. This lighting system also estimates the demand charge associated with the use of the lighting system. This calculator is particularly useful for the design of new lighting installations. You can refer to our guidance document to see how the calculator works before using it.  Guide – LAMP ‘How large should my lighting system be?’ Calculator 

The LAMP Unlimited Lighting Calculator was the first calculator that we created on Project LAMP. This calculator determines how much electricity is required to reach the target DLI every single day of the year. This is our least effective calculator since a lighting system would need to be designed to provide enough light on even the darkest day of the year. That is an unrealistic scenario, because it clearly would not be cost-effective to design your lighting system for the darkest day of the year. Because of that  unrealistic assumption, this calculator does not calculate demand charges, only the cost of the  electricity used. You can follow our guide below to see how the calculator works before trying it. Guide – LAMP ‘Unlimited’ Lighting Calculator  

This is a duplicate of the LAMP basic ‘unlimited’ lighting calculator in an excel spreadsheet with NSRBD information. In addition to selecting the link to this calculator, it is important to also review the guidance document on how to download solar radiation. Along with this calculator, you will need to review the guidance document below that will outline how to download solar radiation for use of this calculator.  Guidance on how to download solar radiation data 

Use the Lamps Needed Calculator 1.1, ©Neil Mattson, Cornell University 2015, to estimate lamp needs for your greenhouse. The calculator will open in Excel. Fill your information in the yellow highlighted fields. Do not modify any boxes or go into the pink fields. Note: the placement of lamps should be determined by a lighting professional for light uniformity in the greenhouse. Lamps needed may be somewhat more if you want uniform lighting edges of the growing space and to account for spillage of light at the edges.  

When thinking about supplemental lighting, it is important to know how much sunlight you have in your location. Joanne Logan (University of Tennessee) and Jim Faust (Clemson University) developed these interactive maps of the average daily light integrals (DLI) throughout the US. You can find monthly averages for the DLI for any location. Keep in mind that this is the DLI outside. To calculate the DLI inside your greenhouse, you need to know how much of the sunlight is transmitted into the greenhouse. Light transmission depends on the glazing material of your greenhouse, how old it is, and how clean it is. Transmission can range anywhere from 35% to 80%.  

Here is a short video on light transmission to support the use of the DLI Maps application. https://www.youtube.com/watch?v=Weu0pj1wivY, produced by the E-Gro team http://www.e-gro.org/.