Conducting Energy Simulation with IES VE: A Step-by-Step Guide
Building energy simulations are critical for designing energy-efficient and high-performance buildings. With a reliable tool like Integrated Environmental Solutions’ Virtual Environment (IES VE), building professionals can gain a detailed understanding of a building’s energy performance and identify opportunities for improvement. This article offers a step-by-step guide to conducting an energy simulation using IES VE.
Step 1: Define the Building Geometry
The first step is defining the building geometry. IES VE provides a feature known as ModelIT for creating 3D models of buildings. In this stage, you sketch the layout and structure of your building, ensuring that all physical dimensions and space allocations are correctly represented.
The building geometry and specifications could be defined as follows:
| Parameter | Ground Floor | First Floor | Second Floor |
|---|---|---|---|
| Total Area (m²) | 800 | 800 | 800 |
| Number of Rooms | 10 | 10 | 10 |
| Room Height (m) | 3 | 3 | 3 |
| Wall Length (m) | Varies | Varies | Varies |
| Wall Height (m) | 3 | 3 | 3 |
| Window Area (m²) | Varies | Varies | Varies |
| Door Area (m²) | Varies | Varies | Varies |
Step 2: Building Fabric Data
Once the building model is set up, the next step is defining the construction materials and thermal properties of the building fabric. This is done in ApacheConstructions, where you specify the U-values of the envelope, the thermal properties of the construction materials, and the glazing specifications. Accurate building fabric data ensures that the building’s thermal performance is accurately represented in the simulation.
Typical values of construction materials and thermal properties of the building fabric:
| Building Component | Material | U-Value (W/m²K) |
|---|---|---|
| External Wall | Brick cavity wall with insulation | 0.30 |
| Internal Wall | Plasterboard | 0.50 |
| Roof | Concrete deck with insulation | 0.25 |
| Ground Floor | Concrete slab with insulation | 0.25 |
| Windows | Double glazing with low-e coating | 1.60 |
| Doors | Insulated metal door | 1.50 |
Please note that these are sample values and the actual values will depend on the specific materials and components used in your building design. The U-values, in particular, are critical as they determine the heat transfer rate through each building element, and can significantly influence the building’s overall thermal performance.
Step 3: HVAC System
The third step involves defining the HVAC system, which can be done using the ApacheHVAC module. This includes the type of HVAC system, its configuration, efficiency, and controls. Defining these factors correctly is crucial, as the HVAC system plays a significant role in a building’s energy consumption.
The following table provides the hypothetical specifications for different types of HVAC systems, such as Variable Refrigerant Flow (VRF) and Variable Air Volume (VAV):
| HVAC System Type | Configuration | Cooling Efficiency (SEER) | Heating Efficiency (HSPF) | Controls | Distribution | Ventilation | Supplemental Heating |
|---|---|---|---|---|---|---|---|
| Variable Refrigerant Flow (VRF) | Distributed | 14.5 | 8.2 | Programmable Thermostat | Ducted | Mechanical with Heat Recovery | Electric Resistance |
| Variable Air Volume (VAV) | Centralized | 12.0 | 7.5 | Building Management System | Ducted | Natural | Gas Boiler |
Step 4: Location and Weather Data
IES VE uses local weather data for its simulations, provided in the form of EPW (Energy Plus Weather) files. These files offer a comprehensive set of weather data required for the simulations, including temperatures, wind speed, solar radiation, and more.
For this step, we’ll choose Delhi, India, as an example. Please note that IES VE uses EPW files for weather data, which contain comprehensive hourly data for a whole year. The table below is a simplified version of what could be found in such a file:
| Parameter | January (average) | April (average) | July (average) | October (average) |
|---|---|---|---|---|
| Dry Bulb Temperature (°C) | 14.6 | 26.4 | 29.4 | 24.2 |
| Dew Point Temperature (°C) | 8.5 | 15.4 | 26.2 | 18.3 |
| Relative Humidity (%) | 77 | 41 | 79 | 69 |
| Wind Speed (m/s) | 2.4 | 3.2 | 3.7 | 2.0 |
| Direct Normal Radiation (W/m²) | 318 | 710 | 452 | 569 |
| Diffuse Horizontal Radiation (W/m²) | 75 | 81 | 97 | 62 |
Please note that these are average values and actual weather conditions will vary throughout the day and the year. Also, remember that for building energy simulation, we typically need an EPW file with hourly data for the entire year. The EPW file contains additional parameters such as atmospheric pressure, cloud cover, precipitation, and others, which are also important for building energy simulation but are not included in this simplified table.
Step 5: Operational and Occupancy Schedules
ApacheSystems is used to define the building occupancy schedule, lighting, and equipment usage. These schedules greatly influence the internal heat gains and the overall energy demand of the building.
The following table provides typical results from an annual energy simulation:
| Energy Simulation Output | Typical Value |
|---|---|
| Total Annual Energy Consumption | 375,000 kWh |
| Peak Cooling Load | 250 kW |
| Peak Heating Load | 200 kW |
| Annual Cooling Load | 150,000 kWh |
| Annual Heating Load | 100,000 kWh |
| Lighting Energy Use | 50,000 kWh |
| Equipment Energy Use | 75,000 kWh |
Keep in mind, these are typical figures. The actual energy consumption and loads of your building will depend on many factors, including its location, construction, usage, and HVAC system. In practice, the simulation will provide much more detailed results, including hourly or monthly energy use, energy use by end use (such as lighting, heating, cooling, equipment, etc.), and potentially many other parameters depending on the level of detail in the simulation.
Step 6: Running the Simulation
Once all the data is inputted, you’re ready to run the simulation. You can use the ApacheSim module to calculate the annual energy consumption, heating and cooling loads, and other parameters. This provides a detailed understanding of the building’s energy performance.
Before running the simulation, it’s important to verify all the data and settings. Here’s a typical checklist that you can follow:
| Checklist Item | Status (✓ or X) |
|---|---|
| Building Geometry Defined | ✓ |
| Building Fabric Data Input | ✓ |
| HVAC System Defined | ✓ |
| Location and Weather Data Imported | ✓ |
| Occupancy and Operational Schedule Defined | ✓ |
| Lighting and Equipment Loads Defined | ✓ |
| ApacheSim Settings Checked | ✓ |
Here’s what each item means:
- Building Geometry Defined: Check that all dimensions, space allocations, and other aspects of the building’s physical structure have been correctly represented.
- Building Fabric Data Input: Ensure that the U-values of the envelope, the thermal properties of the construction materials, and the glazing specifications are accurate.
- HVAC System Defined: Confirm that the type of HVAC system, its configuration, efficiency, and controls have been accurately specified.
- Location and Weather Data Imported: Verify that the correct EPW file has been imported for the building’s location.
- Occupancy and Operational Schedule Defined: Make sure that the building’s occupancy and operational hours have been defined correctly.
- Lighting and Equipment Loads Defined: Check that the lighting and equipment loads have been defined and are reasonable.
- ApacheSim Settings Checked: Go over the ApacheSim settings to ensure that everything is set up for the simulation to run smoothly.
Once all these checks are complete, you should be ready to run the simulation.
Step 7: Interpretation of Results
Interpreting the results accurately is crucial to making effective design or operational changes. IES VE provides detailed outputs that can be analyzed to understand the building’s energy usage patterns and identify areas for improvement.
Step 8: Implementing Energy Efficiency Measures (EEMs)
Based on the simulation results, you can propose several EEMs. These might involve changes to lighting systems, HVAC equipment, building envelope, operational schedules, etc. Once proposed, these EEMs can be applied to the model, and the simulation re-run to estimate potential energy savings.
Here’s a table describing potential Energy Efficiency Measures (EEMs), their impact, and estimated savings based on a simulation.
| EEM | Description | Impact | Estimated Savings (kWh/year) |
|---|---|---|---|
| EEM 1: LED Lighting | Replace conventional lighting with LEDs | Lower electricity consumption for lighting | 15,000 |
| EEM 2: High Efficiency HVAC | Upgrade HVAC system to a higher SEER model | Lower electricity consumption for heating and cooling | 50,000 |
| EEM 3: Improved Insulation | Enhance building envelope insulation | Lower heat loss/gain, leading to lower heating and cooling demand | 25,000 |
| EEM 4: Occupancy Sensors | Install occupancy sensors for lighting control in infrequently used areas | Lower electricity consumption for lighting | 5,000 |
| EEM 5: Efficient Equipment | Replace existing office equipment with energy efficient models | Lower electricity consumption for equipment | 10,000 |
These are typical numbers, and actual savings will depend on various factors such as the specific building design, operation schedule, location, and local weather. Once these measures are implemented in the simulation model, the simulation can be re-run to estimate the new energy consumption and potential savings.
Step 9: Reporting
Finally, you’ll compile the findings into a comprehensive report, detailing the building’s energy performance, proposed EEMs, estimated energy savings, and any recommendations for further improvements.
In conclusion, IES VE provides a comprehensive suite of tools for building energy simulation, helping professionals design buildings that are energy-efficient, comfortable, and sustainable. By following this step-by-step guide, you can conduct an effective energy simulation and drive your building projects towards sustainability and efficiency.