Method of systematic determination of specific thermal characteristics of building

In the paper the classical term «specific thermal characteristics of building» proposed by professor Chaplin V.M. for heating systems developing also for others heat-consuming system for building such as ventilation, air conditioning, hot-water supply system is observed. The followings attributing values are established: external building volume, temperature potential in annual crevice cycle. Introduction The term «specific thermal characteristics of building» was proposed by prof. Chaplin M.V. more than 100 years ago. Primarily this characteristics was applied for pre-project evaluation of followings parameters: a) capacity of heating systems and equipment; b) tentative fuel requirement of building; c) sufficiency and optimality of thermal protection of buildings. This characteristic are widely used at present time including educational programs because the specific capacity of heating systems per 1 m3 of building measured by external dimension. The new application fields of this parameter are proposed for normalization of building energy consumption reflected its energy efficiency. Taking into account the modern building has not only heating system but also three types of thermal-consuming systems (mechanical ventilation, air conditioning, hot-water supply system) that are not completely described in regulatory documents the technical reasonability of extending of the term «specific thermal characteristics of building» for each heating system type takes place. It allows correct estimation of annual total energyconsuming in the building. This idea and concept of the calculation procedures are proposed in 2002 [1] in form of equations. Further development of this idea is reflected in research works [2, 3 etc.], regulatory documents [4, 5], works of developers of the document «SP50.13330-2012» [6] as well as the principle paper about «boundary of analysis» [7], required addition and refinement of earlier data. The paper is devoted to realization of calculation method and the above concepts when design process. a Corresponding author: ProkhorovVI@mgsu.ru DOI: 10.1051/ , 0 (2016) MATEC Web of Conferences matecconf/2016 86 8604068


Introduction
The term «specific thermal characteristics of building» was proposed by prof. Chaplin M.V. more than 100 years ago. Primarily this characteristics was applied for pre-project evaluation of followings parameters: a) capacity of heating systems and equipment; b) tentative fuel requirement of building; c) sufficiency and optimality of thermal protection of buildings. This characteristic are widely used at present time including educational programs because the specific capacity of heating systems per 1 m3 of building measured by external dimension. The new application fields of this parameter are proposed for normalization of building energy consumption reflected its energy efficiency.
Taking into account the modern building has not only heating system but also three types of thermal-consuming systems (mechanical ventilation, air conditioning, hot-water supply system) that are not completely described in regulatory documents the technical reasonability of extending of the term «specific thermal characteristics of building» for each heating system type takes place. It allows correct estimation of annual total energyconsuming in the building.
This idea and concept of the calculation procedures are proposed in 2002 [1] in form of equations.
Further development of this idea is reflected in research works [2, 3 etc.], regulatory documents [4,5], works of developers of the document «SP50.13330-2012» [6] as well as the principle paper about «boundary of analysis» [7], required addition and refinement of earlier data.
The paper is devoted to realization of calculation method and the above concepts when design process.
The necessary requirements are followings: 1) application for every type of heat consumption systems using external building volume Vext for calculation of all rooms [7]; 2) justification of temperature differential for each engineering system (potential heat exchange method by V.N. Bogoslovsky) for every design condition.
Heating systems In this work the classical form of parameter «specific thermal characteristic of building» is following: where: c heat q is calculated specific thermal characteristic of building, applying for heating systems;  (1) is ratio of capacity of heating system cb heat Q to calculated value (tint -text) in working medium (generally, it is air) for internal and external side of building envelope per unit of heat exchange potential. Ratio of heat consumption value (per 1 oC) or «specific» capacity to ext V is specific thermal characteristics of building in case of heating system.
Next stage is to determine analogue values for others heat consuming systems of building by calculation method. Realization of this stage demonstrates comparable (or higher) values of analogues vs. value of c heat q . Thus, they can be used according to common recommendations of energy performance certificate, particularly, for determination of annual heat consumption.
So, extending of term «specific thermal characteristic of building» consists in individual application not to heating system only but for others mechanocaloric systems of building that follows in the Chaplin V.M. theory.
It should be noted, in the bellow methods the common denominator in «external task» (heat-mass exchange of building with environment medium according to prof. V.P. Titov) must be used for constant value of external building volume ext V according to eq. (1), but not internal building volume served by certain mechanocaloric system only. These methods are suitable for «internal tasks» (according to prof. V.P. Titov) only, for exp. when design of air-heat microclimate system as well as when comparison of performance indicator (for exp., energy consumption) for certain systems and served buildings. During a summer season the ventilation systems work without air heating, i.e. only electric energy consumption takes place.
Air conditioning system Heat consumption of conditioner depends of applied air handling scheme. In this work the simplified system (straight-through arrangement) is studied.
As air heating in central air-conditioner is accomplished annually («reheat») the calculation of «specific thermal characteristic» value for building is accomplished for winter and summer seasons separately.
Winter season ) ( During winter season the air heating process with aspirator in many cases (exp. in air conditioners for textile industry) is not taken account. In others cases the difference between in t and ext t ) ( ext in t t is reduced. Required capacity for «reheat» effect is described with the below scheme for summer season. Summer season To provide the temperature of inlet air equal to heat-to-humidity ratio in the building for achievement a required humidity after cooling and drying process the air should be heated even during a summer season (Fig. 1).
is air heating with heating element («reheat») taking into account its partial heating with ventilator; I-Cinternal process; E-C-F -cooling and drying of external air ) ( If in this scheme a ventilator is placed after air-cooling system the value of vent t ' (difference between tc and theat) should be taken account (see Fig. 1).
To simplify the equations, hereinafter the parameter tc is used only (i.e. vent t ' =0).
Also, the ratio of mass flows for both interacting mediums should be considered as air heating is realized in heat exchanger with water. So, the value sc ac Q can be determined for air and water.
Balance equation of heat-exchange is following: where: Gin and Gw are mass flow of heated inlet air and heating water in air heater, kg/s; air c and w c are heat capacities for air and water;

IPICSE-2016
4068 w t ' is temperature difference between input and output of heated water in heat exchanger.
Return temperature of water in heat exchanger depends of initial temperature of interacting flows, air and water flow rates in obstruction-free flow areas and obtained by traditional calculation method. Input water temperature during a summer season is equal to temperature in hot water supply system.
In scheme where water in «reheat» conditioner after water heat exchanger is used for hot water supply system, its temperature can be equal to 55 oC according to SP30-13330-2012 for water supply system in building (i.e. water temperature in water tap).
Advantage of this scheme is highly-accurate monitoring in case of low heat load and small temperature differences in air flow that typical for «retreat» effect. In case of «retreat» effect, air-heater in conditioner is directly connected with flow line on heat system, the max temperature during summer season is 70 o C (during winter season this value is higher that requires reconnection of heat exchanger to return line of heating system).
Temperature differences in these cases presented a heat-change potential for water are followings: -average temperature of return temperature of water calculated for «reheat» air heater.
Temperature differences of air and water flows in «reheat» heat exchanger are related in followings equations: Hot-water supply system For these systems the determination of specific thermal characteristics of building is differed for summer and winter seasons due to variety of cold water temperature.
Winter Q include heat losses through pipes due and to daily and seasonal irregularity of hot water consumption. As the denominator in the eq. (8) and (9) for specific thermal characteristics of building is the temperature difference of water vs. others heat consuming systems where temperature difference of air is used, the reasonability of introduction of universal analog parameter for air heating process with the same thermal capacity with using eq. (6) and (7)