ESP-r Overview

ESP-r allows an in-depth appraisal of the factors which influence the energy and environmental performance of buildings. The ESP-r system has been the subject of sustained developments since 1974 with the objective of simulating building performance in a manner that: a) is realistic and adheres closely to actual physical systems, b) supports early-through-detailed design stage appraisals, and c) enables integrated performance assessments in which no single issue is unduly prominent.
ESP-r attempts to simulate the real world as rigorously as possible and to a level which is consistent with current best practice. By addressing all aspects simultaneously, ESP-r allows the designer to explore the complex relationships between a building's form, fabric, air flow, plant and control. ESP-r is based on a finite volume, conservation approach in which a problem (specified in terms of geometry, construction, operation, leakage distribution, etc.) is transformed into a set of conservation equations (for energy, mass, momentum, etc.) which are then integrated at successive time-steps in response to climate, occupant and control system influences. ESP-r comprises a central Project Manager around which are arranged support databases, a simulator, various performance assessment tools and a variety of third party applications for CAD, visualisation and report generation.

Keywords: energy simulation, environmental performance, commercial buildings, residential buildings, visualisation, complex buildings and systems

Expertise Required: Understanding of thermo-physical processes in buildings, environmental systems and controls as well as domain expertise for electrical, microtoxin and CFD assessment domains (if used).

Users: Primarily in Europe but with users and developers worldwide.

Audience: Engineers, researchers, energy consultants, multi-disciplinary design firms.

Input: Building geometry can be defined via CAD tools, in-built CAD facilities or click-on-grid or image. ESP-r supports a building representation of arbitrary complexity (but most users work with models of 10-50 thermal zones. Models can be exported to other assessments tools such as EnergyPlus, Radiance (visual simulations) or VRML worlds. Constructional and operational attribution is achieved by selecting entities from support databases and associating these with the surfaces and spaces comprising the model. Models can be further attributed to account for temporal shading and insolation patterns, explicit radiation viewfactors, facade-integrated photovoltaic modules, temperature dependent thermophysical properties and CFD domains. As required, component networks can be defined to represent, for example, HVAC systems, distributed fluid flow (for the building-side air or plant-side working fluids) and electrical distribution systems. Alternatively, users can use idealised environmental controls for early design-stage explorations.
Simulations: With ESP-r, functionality follows description - simple models and operating regimes composed in a few minutes can be extended, in steps, to encompass the simultaneous solution of fabric (1/2/3D), air flow (network and/or coupled, transient CFD), electrical power, embedded renewables, plant system components, indoor air quality and lighting assessments via Radiance. Building and flow simulations can be undertaken at frequencies of one minute to one hour and system simulations can be from fractions of a second to an hour.


Output: An interactive results analysis module is used to provide many different views of simulation results, undertake a variety of performance appraisals and explore the interactions between assessment domains. Tools are provided to enable the construction of an Integrated Performance View which summarises performance over a range of relevant criteria. The range of analyses are essentially unrestricted and data can be exported to other analysis and graphing tools (but many users find they rarely need to access spreadsheets).

Computer Platforms: Solaris: Sparc Ultra 5 or newer, 256+MB memory. Linux (Redhat/ Mandrake/ SUSE etc): Pentium III or newer, 256+MB memory (but more memory supports much faster recovery of simulation results). Mac OSX 10.2 or newer with X11 installed 512+MB memory. Windows either via Cygwin emulation environment or as native windows executables (Beta) 512+MB. Disk requirements: ~120MB source distribution, ~135MB executables/ libraries/ example problems, ~500MB user project folders.

Programming Language: C, C++ and FORTRAN (F77 with F90 extensions). The most common compiler is the GNU compiler collection version 3.4 (work is underway to allow compilation under GNU version 4.0 compilers as well as on 64 bit computing environments).

Strengths: In addition to state of the art standard simulation features, ESP-r has powerful capability to simulate many innovative or leading edge technologies including daylight utilisation, natural ventilation, contaminant distribution, combined heat and electrical power generation and photovoltaic facades, adaptive 3D transient CFD, multi-gridding (2D and 3D conduction), and control systems.

Weaknesses: Specialist features require knowledge of the particular subject. Although robust and increasingly used for consulting, ESP-r retains much of the look and feel of a research tool and lacks the extensive databases associated with commercial tools. The current Windows implementation does not conform to the standard look and feel of most Windows applications and lacks a few features available on other platforms. ESP-r does yet provide a built-in undo function. ESP-r dialogs and contextual help messages are a bit heavy on jargon. ESP-r is much better learned via interactions with a mentor than by self-instruction.



Contact: ESRU
Department of Mechanical Engineering
University of Strathclyde
James Weir Building
75 Montrose Street
Glasgow, Scotland G1 1XJ
United Kingdom
telephone +44 (141) 548 3986
facsimile +44 (141) 552 5105

Availability: ESP-r is available via a GPL licence (e.g. anyone to take it and use it for essentially any research or commercial purpose). ESP-r is available for download via the ESRU web site as precompiled distributions for a number of computer platforms. Source code is available from an international server.