INCORPORATING A MODULAR SYSTEM SIMULATION PROGRAM INTO A LARGE ENERGY ANALYSIS PROGRAM: THE LINKING OF IBLAST AND HVACSIM

摘要

Most currently available hourly energy analysisrnprograms utilize separate and sequential simulations ofrnthe building, air handling systems, and primary energyrnplants. This results in a lack of feedback from thernsystem to the building and from the pIant to the systemrnand building. This is especially a problem when anrnundersized system or plant is simulated. If anrnundersized system were actually installed in a buildingrnthe zone cooling and or heating loads could not be metrnall the time causing the temperatures to float out of therndesired range. An integrated building simulation canrnrepresent this condition well but the BLASTrnsimulation, because of its sequential nature cannot. ThernBLAST program has recently been revised to eliminaternthe separate simulations. The resulting integratedrnprogram is called IBLAST and it contains a largernlibrary of system and plant types which can be selectedrnand sized by the user. This work further improves userrnflexibility in defining system and plant arrangements byrnincorporating MODSIM, a program. Element of thernHVACSIM+ package, into IBLAST. The combinedrnprogram is substantially enhanced and retains all of thernfunctionality of both components. In addition,rnMODSIM can obtain all required system parametersrnfrom the IBLAST input file or they may be specified inrna MODSIM data file.rnThe adaptive time step feature of MODSIM isrnutilized to allow the fast responding elements of arnsystem to be simulated at a time step on the order ofrnseconds. The slow response of massive buildingrnelements is simulated at larger time steps, typicallyrnfifteen minutes or longer, which are user specified.rnThe MODSIM time step is always smaller, and adaptsrnto provide an integral number of steps betweenrnIBLAST time steps.rnThis paper presents results obtained usingrnMODSIM systems with IBLAST. Specifically, arnsingle zone draw through and a multizone fan systemrnare illustrated along with a description of the stepsrnrequired to produce the MODSIM connectionrndiagrams for each system. Methods used to símulaternnon-traditional systems are also discussed.