ApacheLoads User Guide - Integrated …

1 Page1of8 ApacheLoadsUser Guide <Virtual Environment> for Heating Loads Loads air ventilation air settings for for Heat Gain Loads ventilation air ventilation air Link?.. Day (for profiles).. for Heat Balance Method time for Autosizing autosized last programASHRAEHeatBalance Method( ApacheLoads ) performs heatloss and heat gain calculations according to the procedures laid down intheASHRAE fromApacheLoadsare displayed by the an account of calculation methods used inASHRAE Heat Balance Method( ApacheLoads )

2 SeeASHRAE Heat Balance MethodCalculation LoadsHeating LoadsimplementsASHRAE procedures for the calculation of roomheating requirements and the sizing of heating room heat losses are calculated in the absence of casual and solarheat gains. The calculation optionallyincludes the effects of mechanical andnatural ventilation air time, day and month of the heating loads calculation can be that the time chosen matches a heated period in the modelled are presented (in the programVistaas tables orgraphsof room or zoneheat loss, broken down by heat loss mechanism.)

3 Losses can be expressed on afloor area or room volume basis. Room temperatures are also displayed. Thedata may be exported to other applications such as spreadsheets and include the following: Radiator a description of the calculation methods used inApacheLoadsseeASHRAE Heat Balance MethodCalculation forHeating LoadsCalculationTick this box to include a Heat Loss calculation when you click on exchangeAir exchangesspecified in Room Dataare divided into three categories: infiltration,auxiliaryventilation and natural ventilation. Any infiltration air exchanges areincluded unconditionally, butauxiliaryand natural ventilation air exchanges may beswitchedon or off at calculation this box if you wish to includeRoom Dataauxiliaryventilation air exchanges inthe Heat Loss exchanges are specified in Room Data in terms of a Maximum Value and aVariation Profile.

4 In Heat Loss the Variation Profile requires interpretation becausethe calculation does not involve the time variable. The assumption is that thePage5of8exchange rate takes the Maximum Value unless the profile is Off continuously or aformula profile (which is not supported byHeating Loads), when it takes the ventilationair exchangeTick this box if you wish to includeRoom Datanatural ventilation air exchanges inthe Heating for natural ventilation are interpretedas for mechanical settings for profilesThe profile settings determine whether heating is available in each room.

5 If theheating profile is off at the specified hour, week day and month there is assumed tobe no heating. In the case of annual profiles the profile is evaluated for the indicatedweekday in the central week of the this button to start theASHRAE Heat Balance Method on this button to leave LoadsCooling Loadscalculates room cooling loads and free-floating temperaturesusingtheASHRAE Heat Balance calculation is carried out for one design day in each of a user-selectedrange of months, using weather data provided in APlocate. The calculationtakes into account the timing and nature of each gain, applying the appropriateradiant fraction toall sources of heat and cooling.

6 Inter-room dynamicconduction and ventilation heat transfer is accounted for. Glazing solartransmission properties are treated using an analysis based on the Fresnelequations. At the user s option the effects of ventilation air exchanges andexternal solar shading, as calculated by SunCast, may be programVistapresents theCooling Loadsresults in tabular or graphicalform in a variety of formats. Gains are broken down by heat transfer mechanismand bytype (sensible or latent). Results may be displayed by room, by zone ortotalled over the building and peak loads are identified.

7 Various measures ofroom temperature are displayed, together with room relative humidity. Data maybeexported to other facilities are provided as follows: Calculation of ventilation supply conditions that will meet the calculatedcooling loads. User-definable tables of a description of the calculation methods used inCooling for Heat Gain LoadsCalculationTick this box to include a Heat Gain calculation when you click on exchangeAir exchanges specified in Room Data are divided into three categories: infiltration,mechanical ventilation and natural ventilation.

8 Any infiltration air exchanges areincluded unconditionally, but mechanical and natural ventilation air exchanges maybe switchedon or off at calculation this box if you wish to includeRoom Datamechanical ventilation air exchangesin the Heat Gain ventilationair exchangeTick this box if you wish to includeRoom Datanatural ventilation air exchanges inthe Heat Gain Link?Tick this box to include the effects of external solar shading, as calculated bySunCast or SunCast Lite, in the HeatCooling is important to ensure that the shading data is kept up to date with any changes tothe building geometry.

9 Theshading calculations should be repeated after any (for profiles)The Heat Gain calculation is carried out for one design day per month. Indicatewhich day of the week is to be used to set the profiles used inCooling Loadsforcasual gains, ventilation rates and (if appropriate) temperature boundary PeriodSelect the months for whichCooling Loadscalculations are on this button to start theHeating and Cooling on this button to leave for Heat Balance Method OptionsOptions for the simulation, see ApacheSim User Guide for OptionsOptions for output to the results viewerVista, see ApacheSim User Guide for time stepSpecify the time step to be used in the simulation.

10 A time step of 10 minutes issuitable for most building period of preconditioning is necessary to ensure thatthe building enters thesimulation period in a realistic thermal state. Preconditioning is necessary becauseof heat storage in the building fabric. For lightweight buildings a preconditioningperiod of 10 days is sufficient. For heavyweight buildings asmuch as 30 days ormore may be needed. The appropriate period of preconditioning may be establishedby increasing the number of preconditioning days until the effect of furtherincrements produces a negligible change in the first day s simulation for Autosizing autosized parametersAuto-sized parametersare the parameters located in the Room Data / ApacheSystems dialogthat are sized during ApacheLoads or ApacheCalccalculations.