前言这是CSA C748《直接膨胀（DX）地源热泵的性能》的第二版。它取代了1994年出版的前一版。本标准新版自上一版起已进行了全面修订。本版本包含CAN/CSA-C13256-1和CAN/CSA-C13256-2中使用的测试方法，这些方法已针对C748进行了调整。新版包含了改进易用性的更改，并包含了反映当前行业实践的更改。本版本中引入的变更包括以下内容:（a）本标准中使用的符号概述；（b） 第1部分和第2部分分别论述了DX对空气和水的影响，包括额定值、性能、测试、标记、安装和额定值公布的要求；（c） 参考出版物已更新，以反映对ISO标准的参考； （d） 自上一版起增加了新的定义；（e）还增加了与试验程序、室内/室外试验方法、仪器和测量有关的新附件。CSA集团非常感谢加拿大自然资源部、安大略省能源部、加拿大电力协会、卑诗省水电公司和马尼托巴省水电公司为制定本标准提供的财政援助。本标准适用于本标准规定范围内的合格评定。范围1。1本标准第1部分涵盖了加热和冷却系统，这些系统通常被称为“直接膨胀到空气热泵”（“DX到空气热泵”）。这些系统通常包括一个带空气流动装置的室内盘管、一个压缩机和一个制冷剂对地热交换器。 系统可以同时提供加热和冷却、仅冷却或仅加热功能。1.2本标准第1部分规定了住宅、商业和工业用工厂制造、电动、机械压缩型DX-to-air热泵的性能测试和评级标准。本标准第1部分中包含的测试和评级要求基于匹配组件的使用。1.3本标准第1部分不适用于单独使用的单个组件的测试和额定值，也不适用于ISO 5151或ISO 13253中涵盖的热泵的测试和额定值。 注:在本标准中，术语“设备”或“热泵”可用于表示“DX至空气热泵”。1.4国际单位制给出的数值为本标准中的记录单位。括号中给出的值仅供参考和比较。 1.5在CSA标准中，“应”用于表示要求，即用户有义务满足的条款，以符合标准；“应该”用于表示建议或建议但不需要的建议；“可”用于表示一种选择或在标准范围内允许的选择；“can”用来表示可能性或能力。注释随附条款不包括要求或替代要求；随附条款的注释的目的是将解释性或信息性材料与文本分开。表和图的注释被视为表或图的一部分，可以作为要求编写。附件被指定为规范性（强制性）或信息性（非强制性）以定义其应用。

PrefaceThis is the second edition of CSA C748, Performance of direct-expansion (DX) ground-source heat pumps. It supersedes the previous edition published in 1994.The new edition of this Standard has been completely revised since the previous edition. This edition incorporates test methods used in CAN/CSA-C13256-1 and CAN/CSA-C13256-2, which have been adapted for the purposes of C748. The new edition incorporates changes to improve ease of use and include changes that reflect current industry practices.Changes introduced in this edition include the following:(a) A summary of the symbols used in this Standard;(b) Part 1 and Part 2 address DX-to-air and water separately, with both including requirements for rating, performance, testing, marking, installation, and publication of ratings;(c) The reference publications have been updated to reflect references to ISO standards;(d) New definitons have been added since the previous edition; and(e) New annexes related to test procedures, indoor/outdoor test methods, and instrumentation and measurements have also been added.CSA Group gratefully acknowledges the financial assistance provided by Natural Resources Canada, the Ontario Ministry of Energy, the Canadian Electricity Association, B.C. Hydro, and Manitoba Hydro in the development of this Standard.This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard.Scope1.1Part 1 of this Standard covers heating and cooling systems that are generally referred to as "direct-expansion-to-air heat pumps" ("DX-to-air heat pumps"). These systems generally include an indoor coil with air-moving means, a compressor, and a refrigerant-to- earth heat exchanger. A system may provide both heating and cooling, cooling-only, or heating-only functions.1.2Part 1 of this Standard establishes performance testing and rating criteria for factory-made, electrically-driven, mechanical-compression type, DX-to-air heat pumps for residential, commercial and industrial use. The requirements for testing and rating contained in Part 1 of this Standard are based on the use of matched assemblies.1.3Part 1 of this Standard does not apply to the testing and rating of individual assemblies for separate use, nor to the testing and rating of heat pumps covered in ISO 5151 or ISO 13253. Note: In this Standard, the terms "equipment" or "heat pumps" may be used to mean "DX-to-air heat pumps".1.4The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.1.5In CSA Standards, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; "may" is used to express an option or that which is permissible within the limits of the standard; and "can" is used to express possibility or capability.Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.Notes to tables and figures are considered part of the table or figure and may be written as requirements.Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.