JESS stands for Java EnergyPlus Simulation Server. It is a software system we have developed to provide remote simulation solutions to EnergyPlus users. JESS Online is the online service with which you can run time-consuming simulation jobs on our high-performance computers. Not only it will free up your computer for other tasks while you are waiting for the results, but running simulations on JESS will also return you results quicker in most cases. Especially, with JESS's acceleration method, simulations can be 5-10 times faster than a standard run. This will let you do a lot more analysis using the model and hence producing better designs.

Why use online simulation? Online simulation is an emerging technology for architectural design and engineering fields. It gives you the ability to access fast computing resources to run multiple simulations in parallel, and lets you do more creative works while waiting for the results. It enables a whole new workflow of handling models and let you do things that were "impossible" before.
What is the advantage of JESS? JESS started its life in 2011 and has grown into probably the most reliable and mature online EnergyPlus simulation service available. To date, it has been tested by over 600 users and executed nearly one million hours of simulations. Performance and compatibility are the key advantages of JESS. We use only the standard releases of EnergyPlus (all versions from 7.0 and above) to ensure the best compatibility. Even with the acceleration method, the results produced by JESS are faithful and compatible with the standard outputs in the majority of cases.
How much does it cost? The JESS service is charged at a flat rate of £0.25 (ex. tax) per hour of computing time. You will be invoiced on a "pay-as-you-go" basis, which means you only pay for what you have used. If you just want to test the system and see how it works, you can get a trial account with 5 hours of simulation time free of charge.
How to get started? JESS is supported by a number of building simulation tools. For example, DesignBuilder has built-in JESS support for both standard/accelerated simulation and optimisation runs. You may also download the standalone JESS Client program, which lets you connect to JESS from all sorts of tools including OpenStudio, EP-Launch, Matlab, and so on. To get started, please first fill in the form for requesting a JESS account.