ANSI AHRI-470-2006 pdf download Performance Rating of Desuperheater/Water Heaters
1.1 Purpose. The purpose of this standard is to establish for Desuperheater/Water Heaters: definitions; test requirements; rating requirements; minimum data requirements for Published Ratings; marking and nameplate data; and conformance conditions.
1.1.1 Intent. This standard is intended for the guidance of the industry, including manufacturers, engineers, installers,contractors and users.
1.1.2 Review and Amendment. This standard is subject to review and amendment as technology advances.
Section 2. Scope
2.1 Scope. This standard applies to Desuperheater/Water Heaters supplied as separate components, as defined in Section 3 and using single component and azeotropic refrigerants only.
2.2 Exclusions. This standard does not apply to Desuperheater/Water Heaters supplied as components of factory-assembled refrigeration or air conditioning units. This standard does not apply to systems using zeotropic refrigerants.
Section 3. Definitions
Definitions. All terms in this document follow the standard industry definitions in the current edition of ASHRAE Terminology of Heating, Ventilation, Air Conditioning and Refrigeration unless otherwise defined in this section.
3.1 Desuperheater/Water Heater. A factory-made assembly of elements by which refrigerant vapor flow and water flow are maintained in such heat transfer relationship that the refrigerant vapor is desuperheated and the water is heated.
3.2 Field Fouling Allowance. Provisions for anticipated Fouling Factor during use.
3.2.1 Fouling Factor. The thermal resistance due to fouling accumulated on the heat transfer surface.
3.3 Net Heating Capacity. The useful heat exchanged between the refrigerant vapor and the water being heated. This value is the product of the mass flow rate of water, the specific heat of water and the water temperature rise, Btu/h [W].
3.3.1 Clean Tube Capacity. This is the Net Heating Capacity of the heat exchanger, Btu/h [W], with clean tubes at the Standard Rating Conditions.
3.4 Published Rating. A statement of assigned values of those performance characteristics, under stated rating conditions, by which a unit may be chosen to fit its application. These values apply to all Desuperheater/Water Heaters of like nominal size and type (identification) produced by the same manufacturer. As used herein, the term Published Rating includes all performance characteristics shown on the unit or published in specifications, advertising or other literature controlled by the manufacturer, at stated Rating Conditions.