Optimisation Objective

 

Comfort

All comfort outputs are for the whole building using an area-weighted average of discomfort calculated for each zone. Note that the comfort-related outputs are termed "discomfort" because by convention DesignBuilder aims to minimise objectives and in the context of standardising optimisation outputs it is better to minimise discomfort than to maximise comfort.

 

• Discomfort (sum clo) - total discomfort hours when summer clothes are worn (see comments below for Discomfort (all clo))
• Discomfort (win clo) - total discomfort hours when winter clothes are worn (see comments below for Discomfort (all clo))
• Discomfort (all clo) - total discomfort hours when winter or summer clothes are worn based on ASHRAE 55 method. Note that this objective is not the same as the building level aggregation method used by EnergyPlus in the Summary output html data which adds up hours in which any zone in the building is uncomfortable. If you would like to only consider occupied hours in your comfort analysis then make sure this option is set in the main Simulation options dialog.

• Discomfort Summer ASHRAE 55 Adaptive 80% Acceptability - Reports whether the operative temperature falls into the 80% acceptability limits of the adaptive comfort in ASHRAE 55-2010 during summer occupied hours. A value of 1 means within (inclusive) the limits, i.e. the zone operative temperature is no more than 2.5°C from than the ASHRAE 55 Adaptive model temperature. A value of 0 means outside the limits (i.e. uncomfortable), and a value of -1 means not applicable, i.e. the running average outdoor air temperature is below 10°C.
• Discomfort Summer ASHRAE 55 Adaptive 90% Acceptability - Reports whether the operative temperature falls into the 90% acceptability limits of the adaptive comfort in ASHRAE 55-2010 during summer occupied hours. A value of 1 means within (inclusive) the limits, i.e. the zone operative temperature is no more than 3.5°C from than the ASHRAE 55 Adaptive model temperature. A value of 0 means outside the limits (i.e. uncomfortable).

• Discomfort Summer CEN 15251 Adaptive Category I - reports whether the operative temperature falls into the Category I (90% acceptability) limits of the adaptive comfort in the European Standard EN15251-2007 during occupied hours when the running mean outdoor air temperature is higher than 10°C. A value of 1 means within (inclusive) the limits, a value of 0 means outside the limits.
• Discomfort Summer CEN 15251 Adaptive Category II - reports whether the operative temperature falls into the Category II (80% acceptability) limits of the adaptive comfort in the European Standard EN15251-2007 during occupied hours when the running mean outdoor air temperature is higher than 10°C. A value of 1 means within (inclusive) the limits, a value of 0 means outside the limits.
• Discomfort Summer CEN 15251 Adaptive Category III - reports whether the operative temperature falls into the Category III (65% acceptability) limits of the adaptive comfort in the European Standard EN15251-2007 during occupied hours when the running mean outdoor air temperature is higher than 10°C. A value of 1 means within (inclusive) the limits, a value of 0 means outside the limits.

Cost

• Capital cost (Capex) - total construction cost as reported on the Cost and Carbon tab. This is the v5.0 equivalent of the Building Construction Capex used in v5.1 and later (see below).
• Operational cost (Opex) - annual cost of the fuel used to operate the building.

• Capital cost (Building Construction Capex) - The basic cost of the building and site construction and is the only option allows when the cost model is set to 1-Basic.

• Capital cost (Building + Design Capex) - The cost of the building + site construction plus the design, overhead and contractor profit costs. This option should only be used when the cost model is set to 2-UNIFORMAT II or 3-NRM1.

• Capital cost (Total Capex) - The cost of the building + site construction plus the design, overhead and contractor profit costs + cost of risk and inflation etc. This option should only be used when the cost model is set to 2-UNIFORMAT II or 3-NRM1.
• LCC total present value - The life-cycle cost calculated by EnergyPlus including the selected type of construction cost

Daylight

No daylight-specific options are available in DesignBuilder v5.

Energy and Loads

• Net site energy is the net energy consumed on site (total site fuel consumption minus any on-site generation). For Simple HVAC, this value is affected by the COP values set on the HVAC tab and is calculated as the sum of the fuel consumption minus any generation. In Detailed HVAC it is the value reported in the Summary ABUPS report, i.e. the sum of the fuel consumption minus generation.
• Net primary energy is the net primary energy due to energy consumed on site (total minus any on-site generation). This output should only be selected when using Detailed HVAC.

• Total site energy is the total gross energy consumed on site. For Simple HVAC, this value is affected by the COP values set on the HVAC tab and is calculated as the sum of the fuel outputs. In Detailed HVAC it is the value reported in the Summary ABUPS report which is also the same as the sum of the fuel consumption reported in the DesignBuilder results.
• Total primary energy is the total primary energy due to energy consumed on site. This output should only be selected when using Detailed HVAC.
• Heating (Electricity) - electricity consumption used in heating
• Heating (Gas) - gas consumption used in heating

• Heating (Oil) - oil consumption used in heating

• Heating (Solid fuel) - solid fuel consumption used in heating

• Heating (Bottled Gas) - bottled gas (e.g. propane) consumption used in heating

• Heating (Other fuels) - Other fuels (e.g. biofuel) consumption used in heating

• Plant heating - equivalent to the Zone Sensible Heating output, the overall sensible heating effect of any air introduced into the zone through the HVAC system including any 'free heating' due to introduction of relatively warm outside air and the heating effects of fans.
• Heating load - same as Plant heating above.
• Cooling (Electricity) - electricity consumption used in cooling
• Cooling (Gas) - gas consumption used in cooling

• Cooling (Oil) - oil consumption used in cooling

• Cooling (Solid fuel) - solid fuel consumption used in cooling

• Cooling (Bottled Gas) - bottled gas (e.g. propane) consumption used in cooling

• Cooling (Other fuels) - other fuel (e.g. biofuel) consumption used in cooling

• Cooling energy - sensible + latent cooling transfer to the supply air from the AHU cooling coil + any single zone unitary and fan coil units in the building.
• Cooling load - same as Cooling energy, above.
• Plant cooling - equivalent to the Zone Sensible Cooling output, the overall sensible cooling effect on the zone of any air introduced into the zone through the HVAC system. It includes any 'free cooling' due to introduction of relatively cool outside air and the heating effect of any fans present.
• DHW (Electricity) - electricity consumption used in DHW
• DHW (Gas) - gas consumption used in DHW

• DHW (Oil) - oil consumption used in DHW

• DHW (Solid fuel) - solid fuel consumption used in DHW

• DHW (Bottled gas) - bottled gas (e.g. propane) consumption used in DHW

• DHW (Other fuels) - other fuel (e.g. biofuel) consumption used in DHW

• AHU heating energy - energy supplied by the AHU heating coil when using Detailed HVAC data.
• Fans - fan energy consumption
• Pumps - pump energy consumption
• Preheat energy - energy supplied by preheat coils to temper the outside air before it enters the outside air mixing box when using Detailed HVAC data.
• Reheat energy - total reheat energy
• Radiant heater energy - total radiant heater energy
• DHW - total DHW energy
• Process energy - total process energy to zones
• Catering energy - total catering gains to zones over the simulation period
• Task/display lighting gains - total task + display lighting gains to zones over the simulation period
• General lighting gains- total general lighting gains to zones over the simulation period
• Misc gains - miscellaneous gains to zones over the simulation period
• Mach gains - process gains to zones over the simulation period
• Cooking gains - catering gains to zones over the simulation period
• Computer gains - computer gains to zones over the simulation period
• Occupancy gains - occupancy gains to zones over the simulation period
• Solar gains internal Windows - solar gains to zones through interior windows over the simulation period
• Solar gains external Windows - solar gains to zones through exterior windows over the simulation period

• Lighting - total lighting energy consumption over the simulation period
• System Fans - System fan energy consumption to zones over the simulation period
• System Pumps - System pump energy consumption
• System Misc - System miscellaneous energy consumption
• Electricity - total annual electricity consumption
• Gas - total annual gas consumption
• Oil - total annual oil consumption
• Solid - total annual solid fuel (typically coal) consumption
• Bot Gas - total annual bottled gas fuel consumption
• Other - total annual other fuel consumption
• Heat Rejection - heat rejection energy by the chillers, e.g. through cooling towers, ground heat exchangers, fluid coolers.
• Generated Electricity - total electricity generated by solar PV and wind.

• Sys sens heating -
• Sys sens cooling -
• Sys lat heating -
• Sys lat cooling -
• Room units -
• Air heating coils -
• Air cooling coils -
• Heat rec sens heat -
• Heat rec total heat -
• Heat rec sens cool -
• Heat rec total cool -
• Chiller load -
• Room Electricity -
• Room Gas -
• Room Oil -
• Room Solid -
• Room Bottled Gas -
• Room Other -

Environmental impact

• Operational CO2 emissions - annual operational carbon emissions due to fuel consumption in the building. Fuel consumption is calculated through an EnergyPlus simulation. Carbon emissions are calculated from fuel consumption using the Carbon emission factors on the Legislative regions dialog.

• LCA (Simple) - Life Cycle Analysis giving the net total lifetime carbon emissions. The sum of the total embodied carbon + operational carbon emissions due to burning of fuel minus beneficial impact of on-site energy generation calculated over the assumed lifetime of the building. Some settings for this including the LCA time of study can be found on the Carbon tab of the Model data dialog. LCA (Simple) is calculated simply as Embodied CO2 + Years of study x Annual Operational CO2 emissions.
• Embodied CO2 - total embodied carbon as reported on the Cost and Carbon tab.

Heat gains

• Glazing gain - thermal conduction gains through windows
• Walls gain - thermal conduction gains through walls
• Ceilings gain - thermal conduction gains ceilings
• Floors gain - thermal conduction gains through floors
• Solid floors gain - thermal conduction gains through ground floors
• Partitions gain - thermal conduction gains through partitions
• Roofs gain - thermal conduction gains through roofs
• Rooflights gain - thermal conduction gains through rooflights
• Ext floors gain - thermal conduction gains through exterior floors
• Sens cooling energy - sensible only cooling transfer from the cooling coil to the supply air.
• Ext airflow gain -
• Ext infiltration gain -
• Ext nat vent gain -
• Ext mech vent gain -

Unmet loads

The unmet load hours KPIs described below are the same values as those reported in the EnergyPlus Summary report. The Unmet load hours are described in more detail in the ASHRAE 90.1 Appendix G PRM Reference topic and also in the DesignBuilder LEED and ASHRAE 90.1 Appendix G User Guide.

 

• Unmet load hours all - number of hours where the heating or cooling setpoints were not met over the simulation period for the whole building.
• Unmet load hours heating - as above but for cooling only.
• Unmet load hours cooling - as above but for heating only.

User defined

No user-defined options are available in DesignBuilder v5.