-- --------------------------------------------------------------------------
--
-- Title      : Draft Standard VHDL 1076.1.1 Packages for Multiple Energy 
--            : Domain Support.
--
-- Library    : This package shall be compiled into a library symbolically
--            : named IEEE.
--
-- Developers : IEEE 1076.1.1 Working Group
--
-- Purpose    : This package contains declarations for modeling in the
--            : thermal energy domain.
--
-- Note       :
--
-- --------------------------------------------------------------------------
--   Modification History :
--
--   Version   Date           Description
--     1.0     6 July 2001    Original version.
--     1.1     4 March 2002   FDL 2001 & BMAS 2001 revisions
--     1.2     31 Aug 2002    DAC 2002 revisions
--     1.3     30 Sep 2002    FDL 2002 revisions
-- --------------------------------------------------------------------------

library IEEE;
    use IEEE.FUNDAMENTAL_CONSTANTS.all;

package THERMAL_SYSTEMS is
   -- type declarations

   -- subtype declarations (no thermal resistance or capacitance?)
   subtype TEMPERATURE         is REAL tolerance "DEFAULT_TEMPERATURE";
   subtype HEAT_FLOW           is REAL tolerance "DEFAULT_HEAT_FLOW";
   subtype THERMAL_CAPACITANCE is REAL tolerance "DEFAULT_THERMAL_CAPACITANCE";
   subtype THERMAL_RESISTANCE  is REAL tolerance "DEFAULT_THERMAL_RESISTANCE";

   -- attribute declarations
   -- CORRECT UNITS?
   attribute UNIT of TEMPERATURE         : subtype is "Kelvin";
   attribute UNIT of HEAT_FLOW           : subtype is "Joule/second";
   attribute UNIT of THERMAL_CAPACITANCE : subtype is "Joule-Kelvin";
   attribute UNIT of THERMAL_RESISTANCE  : subtype is "Kelvin-second/Joule";
   attribute SYMBOL of TEMPERATURE         : subtype is "K";
   attribute SYMBOL of HEAT_FLOW           : subtype is "J/s";
   attribute SYMBOL of THERMAL_CAPACITANCE : subtype is "J-K";
   attribute SYMBOL of THERMAL_RESISTANCE  : subtype is "K-s/J";

   -- nature declarations
   nature THERMAL is
      TEMPERATURE across
      HEAT_FLOW   through
      THERMAL_REF reference;
   nature THERMAL_VECTOR is array (NATURAL range <>) of THERMAL;

   -- another nature with entropy as through variable?

   -- vector subtype declarations
   subtype TEMPERATURE_VECTOR         is THERMAL_VECTOR'across;
   subtype HEAT_FLOW_VECTOR           is THERMAL_VECTOR'through;
   subtype THERMAL_CAPACITANCE_VECTOR is REAL_VECTOR       tolerance "DEFAULT_THERMAL_CAPACITANCE";
   subtype THERMAL_RESISTANCE_VECTOR  is REAL_VECTOR       tolerance "DEFAULT_THERMAL_RESISTANCE";

   -- attributes of vector subtypes
   attribute UNIT of TEMPERATURE_VECTOR         : subtype is "Kelvin";
   attribute UNIT of HEAT_FLOW_VECTOR           : subtype is "Joule/second";
   attribute UNIT of THERMAL_CAPACITANCE_VECTOR : subtype is "Joule-Kelvin";
   attribute UNIT of THERMAL_RESISTANCE_VECTOR  : subtype is "Kelvin-second/Joule";
   attribute SYMBOL of TEMPERATURE_VECTOR         : subtype is "K";
   attribute SYMBOL of HEAT_FLOW_VECTOR           : subtype is "J/s";
   attribute SYMBOL of THERMAL_CAPACITANCE_VECTOR : subtype is "J-K";
   attribute SYMBOL of THERMAL_RESISTANCE_VECTOR  : subtype is "K-s/J";

   -- subnature declarations

   -- object declarations (no quantities)

   -- operation declarations (e.g., subprograms)

   -- alias declarations
end package THERMAL_SYSTEMS;