DOE-2 Reference Manual Version 2.1 - DOE2.com

MIN-FLUIO-T in the SYSTEM-FLUID instruction), heat is added from a boiler orother heat source. No heat is added or rejected when heating and cool ingrequir~ments b~lance .. The most common hydronic h~at pump systems maintain thewater ln the clrCUlatlng loop between 70 F and 90 F.circulating piping loop to be uninsulated.This allows theThe heat rejection unit (evaporative condenser or cooling tower), heatingunit, and circulating pump are simulated by the PLANT program.The program assumes that the heat pump requires COOLING-EIR Btu ofequivalent electrical energy for each Btu of heat extracted from the space,and HEATING-EIR Btu of equivalent electrical energy for each Btu of heat addedto the space. Of course, COOLING-EIR is corrected by COOL-EIR-FT,COOL-EIR-FPLR, and RATED-CEIR-FCFM, using either the default curves or theuser-supplied curves. The same is true for HEATING-EIR.Note that the heat pump units, particularly in the smaller sizes equippedwith direct-drive fans, may not be available with a fan capacity that matchesthe calculated value. Similarly, heat pump units that can match both calculatedheating and calculated cooling requirements are probably not available.Therefore, assignment of the heating capacity, cooling capacity, and fancapacity of a' specific, commercially available heat pump unit is recommendedfor improved simulation accuracy. An alternative to assigning fan capacity isto select an available fan with a rated capacity relatively close to thecalculated fan capacity and then specify data for the keyword RATED-CFM (seeZONE-AIR subcommand).A number of optional features and control strategies can be specified forthis system. The optional features are discussed in Table IV.2 and thesection entitled, "Explanation of System Options" (immediately following TableIV.2). The possible control strategies for this system are discussed in Sec.B.5 of this chapter. It is highly recommended that the user read that portionof Sec. B.5 that is applicable to thlS system.Table IV.17 shows the commands and keywords that must be entered forsimulation of this system, as well as those that are applicable but optional(i.e., program uses default value if entry is omitted.)I V. 72 (Revised 5/81)