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:

1. Building Geometry Defined: Check that all dimensions, space allocations, and other aspects of the building’s physical structure have been correctly represented.
2. 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.
3. HVAC System Defined: Confirm that the type of HVAC system, its configuration, efficiency, and controls have been accurately specified.
4. Location and Weather Data Imported: Verify that the correct EPW file has been imported for the building’s location.
5. Occupancy and Operational Schedule Defined: Make sure that the building’s occupancy and operational hours have been defined correctly.
6. Lighting and Equipment Loads Defined: Check that the lighting and equipment loads have been defined and are reasonable.
7. 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.