Designing thermal units
Designing, requirements for the installation of units for commercial accounting of thermal energy and heat-regulating equipment
The equipment and commissioning of the heat energy monitoring unit and / or thermal control equipment are carried out in the presence of a project developed and agreed upon in accordance with the design standards. The project is carried out to determine specific technical and engineering decisions, the estimated cost of construction and for the construction and installation work (working drawings).
Designing units for the calculation of thermal energy and heat-regulating equipment must be carried out in one stage - a working project. The reason for the design is the design task (technical specifications and specifications) and the initial data that must be provided to the designer by the customer of the construction before the start of the design work.
The composition, procedure for the development, approval and approval of the design documentation for the node of heat energy accounting is determined by the current normative documents on design in the construction.
The design documentation for the accounting unit consists of the following sections:
1. Explanatory note which includes:
- the title page;
- details of the developer and customer of the project;
- initial data for designing - in this section in a systematic way the information (provided by the customer of the construction and received as a result of engineering research) about the thermal and hydraulic characteristics of the heat utilization system or the heat network, for which the equipment of the unit of thermal energy accounting is provided, is provided;
- a brief statement of the grounds for designing and the list of values, which calculation is expected to be carried out (amount of thermal energy, maximum and average for a certain period of coolant consumption, average for a certain period of time the temperature of the coolant, instantaneous values of the coolant pressures in the feed and return pipelines);
- a brief description of the object - a brief description of the architectural and planning characteristics of the building, or housing in the building, within which it is planned to place the equipment and pipelines of the unit of heat energy accounting;
- engineering calculations data - the calculation formulas should be given in this section and the results of the hydraulic calculation of the thermal energy accounting unit and the calculation of heat losses in pipelines from the location of the balance sheet membership (operational responsibility, distribution point) to the design location of the accounting point are given. Hydraulic calculation is carried out in order to determine the design cost of the coolant and the study of the influence of hydraulic resistance of the pipeline armature and devices of the unit of thermal energy accounting for the mode of operation of the system of heat utilization (thermal network). The results of the hydraulic calculation are the basis for determining the conditional (nominal) dimensions of the equipment and parts of the pipeline of the unit of thermal energy accounting. The results of the calculation of heat losses can be used in the future for commercial calculations between the heat energy supplier and the subscriber.
2. Drawings including:
- a list of general data with a list of all sheets of the project, references to normative documents, the materials of which are used;
- schemes of principle solutions of heat engineering, electric and part of control and measuring devices;
- specification of equipment and materials;
- Estimated documentation.
In the case of a small amount of project, parts of it can be combined in an explanatory note.
At the request of the customer of design work, other sections and / or types of exploratory work may be included in the project.
The Project Output for design section should include at least the following data:
- the location of the balance of the balance (operational liability) or the distribution point between the district heating company and the subscriber;
- design location of the point of accounting for the release (consumption) of heat energy;
- type of heat supply system (closed water, open water, steam);
- Estimated thermal load of the heat utilization system (heat network) at the design point of accounting;
- technological characteristic of central or local regulation of the supply of heat energy to the system of heat utilization (heat network);
- available and design for the heat utilization system (heat network) the value of the heat carrier pressure in the feed and return pipelines of the heat utilization system (heat network) at the point of accounting;
- nominal sizes of pipelines and pipeline valves, actually available at the time of design in a place where the equipment of the unit of heat energy accounting is assumed.
When designing a solution for the engineering equipment of the heat energy monitoring unit, the designer must provide for the design of the unit of accounting the following elements:
1) means of measuring equipment designed to measure the amount of heat energy released (consumed) by the system of heat utilization or heating network,? For the use of the measured values obtained during commercial calculations. This item is required for the design of the accounting unit;
2) means of measuring equipment designed to measure the quality of the heat supply (average for a specified period of time of the coolant temperatures in the feed and return pipelines, the pressure, the difference in pressure of the coolant in the feed and return pipelines, or the values derived from them, the difference in masses of the coolant, passed through the supply And reverse pipelines for the billing period),? For use of the values obtained as a result of measurements during commercial calculations. This element should be provided in the design of the accounting unit at the request of the customer of the project;
3) measuring instruments, designed to measure instantaneous values of the coolant parameters (pressures and temperatures)? For technological control of the parameters of the coolant. This item is required for the design of the accounting unit;
4) pipeline fittings designed to quickly and reliably disconnect the equipment and pipelines of the accounting unit from the heat network and / or the system of heat utilization, the drain of the coolant and the release of air from the pipelines? To ensure the safe and efficient operation of the thermal energy monitoring unit. This item is required for the design of the accounting unit;
5) devices for cleaning the coolant in order to provide the metrological characteristics of the node of accounting. Such elements are mandatory for the design of the accounting unit.
When choosing the engineering equipment of the heat energy monitoring unit, it is necessary to ensure that the following requirements are met:
- for equipment of the heat energy accounting unit, means of measuring equipment, types of which are entered in the State Register of Measuring Instruments, or means of measuring equipment, which have passed the State metrological certification, must be provided;
- measuring ranges of measuring equipment (upper limit of temperature range (pressure scale), lower limit of temperature range (pressure scale), upper limit of temperature difference (pressure drop), lower limit of temperature difference (pressure drop), upper limit of flow, lower limit of flow , Upper limit of thermal power) should correspond to the range of changes in the parameters of the coolant at the point of reference. In this case, it is necessary to foresee the possibility of using the specified means of measuring equipment in conditions of automatic regulation of the amount of heat energy released or consumed;
- mechanical (strength) characteristics of the measuring equipment, pipeline fittings, protection against pollution, direct pipes, their connections and connecting elements (conditional pressure, maximum operating temperature) should correspond to the working pressure and operating temperature of the coolant for the system of heat use ( Thermal network);
- the working (operational) characteristics of the measuring equipment must be such as to ensure the proper functioning of means with an average revenge of work - not less than ten thousand hours and average service life - not less than eight years;
- the working (operational) characteristics of the pipeline armature of the means of protection against pollution must be such as to ensure the proper functioning of the armature and means with an average revenge for work - no less than thirty thousand hours and average service life - not less than twenty years;
- the pipeline armature must be provided on the pipeline before and after the installation of the measuring equipment, the down cock shall be foreseen at the lowest, and the cock for air discharge - at the highest point of the pipelines of the accounting unit;
- the nominal diameters of the pipeline armature should be determined provided the most effective ratio of the cost of the valve to the pressure loss on it at the calculated cost of the coolant;
- for the equipment of the unit of heat energy accounting, it is necessary to provide convenient, protected from unauthorized access the premises with a reliable waterproofing, a drainage trap, lighting, sufficient for taking displays of settlement means of accounting.
When designing a solution for engineering equipment, the site for the calculation of thermal energy should be based on technical data and take into account the requirements and recommendations for the installation of measuring equipment, piping valves, pollution protection and connecting elements of the pipeline, as set forth in the manufacturer's operating documentation and regulatory documents Design and operation of heat networks and systems of heat utilization.