|
2. Terminology/Symbols |
| 2.0.1 |
Outdoor mean air temperature during heating
period (te)
The average value of day-to-day outdoor mean air temperature during
heating period. |
| 2.0.2 |
Degree days of heating period (Ddi)
The temperature difference between indoor basic air temperature 18oC
and outdoor daily mean air temperature during heating period multiplied
by the number of heating days. Unit is C ¡Pd. |
| 2.0.3 |
Energy consumed for heating (Q)
Energy consumed for heating buildings. Energy consumed for space heating
in this standard mainly means heat consumption of buildings and coal consumption
for space heating. |
| 2.0.4 |
Index of heat consumption of building
(qH)
At outdoor mean air temperature during heating period, to maintain
indoor design air temperature, heat consumed in unit time by unit floor
area and to be supplied by indoor heating device. Unit: W/m2. |
| 2.0.5 |
Index of coal consumption for space heating
(qc)
At outdoor mean air temperature during heating period, to maintain
indoor design air temperature, standard coal consumed during a heating
period by unit floor area. Unit: kg/m2. |
| 2.0.6 |
Index of design heating load for building
(q)
At outdoor design air temperature during heating period, to maintain
indoor design air temperature, heat supplied by heating boilers or other
heating facilities in unit time for unit floor area. Unit: W/m2. |
| 2.0.7 |
Overall heat transfer coefficient of building
envelope (K)
Air temperature difference between both sides of building envelope
is 1K, heat transfer rate through unit area of building envelope within
unit time.
Unit is W/( m2 K). |
| 2.0.8 |
Correction factor for overall heat transfer
coefficient of building envelope (ei )
Building envelopes in various regions and with different orientations,
due to the effect of the radiation from the sun and the sky, make the heat
transfer rate changing within unit time through unit area of building envelopes
under 1K of air temperature difference between both sides of building envelope.
The ratio of changed heat transfer rate to the original one without affection
of radiation from the sun and the sky is correction factor for overall
heat transfer coefficient of building envelope. |
| 2.0.9 |
Shape coefficient of building (S)
Ratio of exterior surface area of building exposing to the air to the
volume enclosed by it. Exterior surface area excludes the areas of ground,
partition of staircases and house door without heating. |
| 2.0.10 |
Area ratio of window to wall
Ratio of window opening area to elevation unit area of room (i.e. area
enclosed by storey height of building and axil line of bay). |
| 2.0.11 |
Heating system;
System composed of boiler plant, outdoor heating network, indoor heating
pipe line and radiators etc. |
| 2.0.12 |
Capacity of boiler plant
Also called rating capacity. Rating capacity of boiler uses unit MW. |
| 2.0.13 |
Boiler efficiency
Ratio of available heat generated by boiler and that contained by burning
coal. Under different circumstances they can be divided into rating boiler
efficiency and boiler operating efficiency. |
| 2.0.14 |
Rating boiler efficiency
Also called rating efficiency. The boiler efficiency under design condition. |
| 2.0.15 |
Boiler operating efficiency (h2
)
The boiler efficiency under real operation condition. |
| 2.0.16 |
Heat transport efficiency of outdoor heating
network (h1 )
Ratio of total output heat of heating network (total input heat minus
heat loss at different sections) and total input heat of heating network. |
| 2.0.17 |
Ratio of electricity consumption to transported
heat
At outdoor and indoor design air temperature, ratio of theoretical
electricity consumption by daily pump and heat daily supplied by heating
system, taking the same units, no dimension. |
|
3. Index of heat loss of building and
coal consumption |
| 3.0.1 |
Index of heat consumption of buildings should be calculated
in the following formula:
(3.0.1)
where
qH - index of heat consumption of building (W/m2)
qH ¡PT- heat transfer loss of unit floor area
through building envelope (W/m2)
qINF - air infiltration heat loss of
unit floor area (W/m2)
qI ¡PH - heat gain of
unit floor area from the inside of building (including cooking, lighting,
electrical appliance and heat released from human beings), taking 3.80
W/m2 for residential building. |
| 3.0.2 |
Heat transfer loss of unit floor area through
building envelope should be calculated in the following formula:
(3.0.2)
where
ti = mean indoor temperature for calculation of all rooms.,
taking 16 for normal residential building;
te= outdoor mean air temperature (
oC )during
heating period should follow Table A of Appendix
A of this standard;
ei= correction factor for overall
heat transfer coefficient of building envelope should follow Table
B of Appendix B of this standard;
Ki= overall heat transfer coefficient of building envelope
[W/(m2K)], exterior wall should take its mean heat transfer
coefficient and calculation method refers to Appendix
C of this standard;
Fi= area of building envelope ( m2 )should be
calculated according to the specifications of Appendix
D of this standard;
Ao= floor area (m2) should be calculated according
to the specifications of Appendix D of this
standard.
|
| 3.0.3 |
Air infiltration heat loss of unit floor
area should be calculated in the following formula:
(3.0.3)
where
Cr -- heat capacity of air, taking
0.27 W ¡P h / (kg¡P K);
r -- air density (kg/m2), taking
the value under te;
N -- air-exchange rate, taking 0.5 1/h for residential building;
V -- air-exchanged volume (m3). It should be calculated
according to the specifications of Appendix D
of this standard. |
| 3.0.4 |
Index of coal consumption for space heating
should be calculated in the following formula:
(3.0.4)
where
qc - index of coal (standard coal) consumption for space
heating (kg/m2);
qH - index of heat consumption of building (W /m2);Z
- heating days should follow Table A of Appendix
A of this standard;
Hc - heat value of standard coal, taking 8.14X103
Wh/kg;
h1- heat
transport efficiency of outdoor heating network, taking 0.85 before energy
saving measures are taken, and 0.90 after taking measures
h 2 - boiler
operating efficiency, taking 0.55 before energy saving measures are taken,
and 0.68 after taking measure
|
| 3.0.5 |
Index of heat consumption and coal consumption
for heating residential buildings in various regions should not exceed
the numeral values in Table A of the Appendix
A of this standard. |
| 3.0.6 |
Thermal insulation levels of building envelopes
for dormitories, guest houses, restaurants and nurseries etc. should reach
the same levels as heating residential buildings in the same region. |
|
4. Thermo-technical design
for buildings |
| 4.1 |
General specifications |
| 4.1.1 |
Buildings are suitable to be designed in south-north
orientations or close to that. Main rooms are suitable to avoid prevailing
wind direction in winter. |
| 4.1.2 |
Shape coefficients of buildings are suitable
to be 0.30 and below 0.30. If it is over 0.30, the thermal insulation for
roofs and exterior walls should be upgraded. Heat transfer coefficients
should be in compliance with the specification in Table
4.2.1. |
| 4.1.3 |
Windows and doors should be designed for staircases
and exterior corridors of heating residential buildings. In the regions
where outdoor mean air temperature is -0.1 to -6.0 during heating period
and no heating for staircases, thermal insulation measures should be taken
for the partition of staircases and house doors. In the regions below -6.0
, heating should be provided for staircases, and facilities against wind
such as porch should be designed for entrance. |
|
| 4. 2 |
Design of building envelope |
| 4.2.1 |
Heat transfer coefficients of building envelopes
elements of heating residential buildings in various regions should not
exceed the limitation values in Table 4.2.1. |
| 4.2.2 |
When heat transfer coefficients of windows have
been in practice taken 0.5 and 0.5 plus lower than the numeral values in
Table
4.2.1, under the condition of satisfying the heat consumption index
specified in this standard, heat transfer coefficient of exterior walls
and roofs could be recalculated and decided by the measures in 3.01--3.0.3
of this standard. |
| 4.2.3 |
Under the condition of being effected by heat
bridge of concrete beams and columns at periphery, mean heat transfer coefficients
of exterior walls should not exceed the limitation values in Table
4.2.1. |
| 4.2.4 |
Area of windows (including transparent
upper part of balcony door) is not suitable to be too large. Area ratio
of windows to walls in different orientations should not exceed the numeral
values in Table 4.2.4.
Area ratio of windows to walls in different orientations
Table 4.2.4
| Orientations |
Area ratio of windows to walls
|
| North |
0.25
|
| East, West |
0.30 |
| South |
0.35 |
|
| |
Note: If area ratio of windows to walls exceeds
the numeral values in the above table, heat transfer coefficients of building
envelope such as exterior wall and roof etc. should be adjusted, so that
heat consumption index of buildings will be in compliance with the specifications. |
| 4.2.5 |
In design, windows (including balcony door)
with good tightness should be used. The class of tightness of windows for
one to six stories buildings should not be lower than Class 3, which are
specified in the current national standard methods for graduating and inspecting
air permeability of windows¡¨ (GB7107), and for buildings have
7 to 30 stories, they should not be lower than Class 2 specified in the
above standard. |
| 4.2.6 |
When buildings are installed with air tightness
windows or windows with seals, rooms should be equipped with adjustable
air exchangers or other available air exchange facilities. |
| 4.2.7 |
Thermal insulation measures should be taken
for the locations of building envelope, where heat bridge occurs, to ensure
its interior surface temperature not lower than indoor air dew point temperature
and to decrease additional heat transfer loss. |
| 4.2.8 |
At the regions where outdoor mean air temperature
during heating period is lower than -5.0, thermal insulation measures should
be taken for vertical wall surfaces below outdoor grade of exterior building
walls and the ground directly touching soil at building periphery. Heat
transfer coefficients of vertical wall surfaces below outdoor grade should
not exceed heat transfer coefficient limitation values of peripheral ground
in Table4.2.1. Heat transfer coefficients of
ground at the periphery of exterior wall within 2.0m from the inner side
of exterior wall should not exceed 0.30W/(m2K). |
|
5. Heating design |
| 5.1 |
General specifications |
| 5.1.1 |
For heating residential buildings,
heat and power co-generation plants and district boiler plants should be
taken as main heating sources. For the buildings near factories, industrial
surplus energy and waste heat should be utilized. |
| 5.1.2 |
In residential quarters newly-built in cities,
if no co-generation, no industrial surplus energy and no waste heat can
be used locally, central heating boiler plants should be set up as heating
source. The capacity of each boiler in the plant is not suitable to be
smaller than 7.0 MW, and heating building area , not smaller than 100,000
m2. For smaller residential quarters, the capacity of each boiler
can be cut down a little bit, but not smaller than 4.2 MW each. During
setting up new boiler plants, the possibility of connecting urban district
heating network should be taken into consideration. Boiler plants are suitable
to be set up near the areas with large heat load density. |
| 5.1.3 |
Heating system for newly-built residential buildings
should be designed with continuous heating mode. Heating modes for commercial/cultural/other
public buildings in residential quarters and for living quarters near factories
can be determined according to the usage and heating requirements and on
the basis of technical and economic comparison. |
| 5.2 |
Heating system |
| 5.2.1 |
While designing heating system, detailed investigation
and calculation on heat loading should be carried out, to determine reasonable
scale and radii of heating system. If the system is at large scale, indirectly
connected primary and secondary water systems are suitable, so as to enhance
operating efficiency and reduce power consumption. Water temperature should
be designed as 115-130 for primary water supply, 70-80 for return water
temperature. ¡@ |
| 5.2.2 |
While designing indoor heating system, designers should
consider the possibility of using heat allocation metres for each family
to control temperature room by room. The surface area of radiators in rooms
should be rationally selected according to design heat load. Indoor heating
systems are suitable to be arranged in loops separately for rooms facing
south and north. When heating main pipelines without insulation exist in
heating rooms, the heat released from main pipes into the room should be
taken into account. ¡@ |
| 5.2.3 |
In design hydronic balance calculation should be made for
heating system, to ensure water flow in each loop to meet design requirements.
Balancing valves or hydronic balancing elements should be installed on
heating supply water pipes (or return water pipes) at inlets of outdoor
loops and buildings and hydronic balancing adjustments are made. The possibility
of heating within different time should be considered for the system with
identical heat source but different types of users. ¡@ |
| 5.2.4 |
While designing heat exchanger station, indirectly-connected
heat exchanger station should select heat exchangers of tight structure,
high heat transfer coefficient and long service life. Heat transfer coefficient
is suitable to be larger than or equal to 3000W/ (m2K). Directly and indirectly-connected
stations should be equipped with automatic or manual adjusting devices. |
| 5.2.5 |
Selection of boiler types should match the coal type supplied
locally on long term. Rating boiler efficiency should not be lower than
the numeral values in Table 5.2.5.
Lowest rating boiler efficiency (%)
Table 5.2.5
| fuel type |
fuel heat value (kJ/kg) |
boiler capacity (MW) |
| 2.8 |
4.2 |
7.0 |
14.0 |
27.0 |
| bitu minous coal |
I |
15500-19700 |
72 |
73 |
74 |
76 |
78 |
| II |
>19700 |
74 |
76 |
78 |
80 |
82 |
|
| 5.2.6 |
Total installed gross capacity of boiler plant should
be decided in the following formula:
QB=Qo / h1
(5.2.6)
where QB - total installed gross capacity of boiler plant
(W);
Qo - design heating load carried by boiler (W);
h1 - heat
transport efficiency of outdoor heating network, usually taking 0.90.
¡@
|
| 5.2.7 |
In newly-built boiler plant, 2-3 sets of boilers may be
installed. If it operates at lower than design load, the operating load
of a single boiler should not be lower than 50 % of rating load.
¡@ |
| 5.2.8 |
Blast blower, inducing fan and dust collector are suitable
to be equipped for each boiler, matching their capacity with boiler. Power
consumption of selected equipment is suitable to be lower than or close
to the values in Table 5.2.8. In design various kinds
of waste heat from boilers should be fully utilized.
Match index of blast blowers and inducing fans of boilers with
bituminous coal II and III
Table 5.2.8
| fan type |
blast blower |
inducing fan |
boiler capacity
MW (t/h) |
flow rate m3/h |
matched motor power kW |
flow rate m3/h |
matched motor power kW |
| pressure Pa (mmH2O) |
pressure Pa (mmH2O) |
| 2.8 (4) |
6000
508 (52) |
2.2 |
10590
2225 (27) |
10.0 |
4.2 (6 ) |
9100
1362 (139) |
5.5 |
16050
2097 (214) |
13.0 |
| 7.0 (10) |
14760
1352 (138) |
7.5 |
25200
2097 (214) |
22.0 |
| 14.0 (20) |
29520
1252 (138) |
17.0 |
50400
2097 (214) |
40.0 |
| 27.0 (40) |
59040
1352 (138) |
30.0 |
100800
2097 (214) |
75.0 |
|
| 5.2.9 |
Primary and secondary water circulating pumps should select
high energy efficiency and low noisy ones, 2 sets are suitable, one is
working and the other is stand-by. When system capacity is larger, more
sets can be added rationally, but the working mode of ¡§large
flow, small temperature difference¡¨ should be avoided. Selection
of primary water pump should consider the possibility of adjusting flow
changes stage by stage. Water quality in system should be in compliance
with the specifications of current national standard ¡§ Standard
of water quality in hot water boilers¡¨ (GB1576). When boiler
capacity is large, it is suitable to install de-oxygen apparatus.
¡@ |
| 5.2.10 |
In design the requirements of parameter monitor and measurement
should be put forward for entrances of boiler plants, heat exchanger stations
and buildings. The temperature-meter for supply and return water, pressure
gage and heat allocation meter (or hot water flow-meter) should be installed
at inlets of boiler room, heat exchanger station and each independent building.
Water meter should be put for water make-up system. Electricity consumed
by power in boiler plant, water pump and lighting should be measured separately.
Larger plant with capacity of single boiler exceeding 7.0 MW should be
equipped with computer system to monitor it. |
| 5.2.11 |
Power consumption of primary and secondary water for hot
water space heating system should be controlled. Usually, the ratio of
power consumption to heat transport, ie, EHR, power consumption to transport
unit heat in design, should not be larger than the value obtained from
the following formula:
(5.2.11)
where
EHR - power consumption to transport unit heat in design, no
dimension;
SQ - daily heat supplied by system (kWh);
e - daily power consumption of water pump
in theory (kWh);
t - daily working hours by water pump,
=24 h while continuous working;
N - rating brake power of water pump (kW);
q - index of design heating load (kW/m2);
A - heating building area of system (m2)
£Gt - design temperature difference between supply and return
water, for primary network, t=45-50, for secondary network, t=25;
SL - total length of main pipe line of outdoor
heating network (including water supply and water return pipes).
when
SL
500m, a= 0.0115;
500m<SL<1000m, a= 0.0092;
SL 1000m,
a= 0.0069
EHR values of primary and secondary networks calculated by formula
(5.2.11) are shown in Table 5.2.11.
EHR values
Table 5.2.11
| Total length of main pope line
of network L (m) |
Design temperature difference
between supply water and return water |
| 50oC |
45oC |
25oC |
| 200 |
0.0018 |
0.002 |
0.0037 |
| 400 |
0.0021 |
0.0023 |
0.0042 |
| 600 |
0.0022 |
0.0024 |
0.0044 |
| 800 |
0.0024 |
0.0026 |
0.0048 |
| 1000 |
0.0025 |
0.0027 |
0.0050 |
| 1500 |
0.0027 |
0.0030 |
0.0055 |
| 2000 |
0.0031 |
0.0035 |
0.0062 |
| 2500 |
0.0035 |
0.0039 |
0.0070 |
| 3000 |
0.0039 |
0.0043 |
0.0078 |
| 3500 |
0.0043 |
0.0047 |
0.0085 |
| 4000 |
0.0047 |
0.0052 |
0.0093 |
|
| 5.3 |
Pipe laying and insulation |
| 5.3.1 |
While designing primary and secondary hot water
networks, economical and rational layout should be taken. For courtyard
network and secondary network, direct burry laying is suitable, while for
primary network, when pipe diameter is larger and underground water level
is not high, ditch laying can be adopted. |
| 5.3.2 |
The thickness of insulation materials
for heating pipes should be determined in accordance with the calculation
formula of economic thickness in current national standard ¡§Guidelines
of insulation design for equipment and pipes¡¨ (GB8175).
¡@ |
| 5.3.5 |
When temperature difference between heating
media and air around heating pipes is equal or lower than 60, the insulation
thickness for heating pipes laid in ditches of outdoor or indoor should
not be lower than the numeral values in Table 5.3.3.
¡@ |
| 5.3.4 |
When other insulation materials are selected
and their heat conductivity coefficient is quite different from the values
in Table 5.3.3, minimum insulation thickness should
be modified as the following formula:
d ¡¦min = l¡¦m
¡P
d ¡¦min /
l
m
(5.3.4-1)
where
d ¡¦min - modified minimum
insulation thickness (mm);
d ¡¦min - minimum insulation
thickness in the table;
l ¡¦m - heat conductivity coefficient
of actually-selected insulation materials at mean operating temperature
[W/(m ¡PK) ];
l m - heat conductivity coefficient of insulation
materials in the table at mean operating temperature [W/(m ¡P K)
].
When the temperature difference between actual heating media and
air around pipes is larger than 60, the minimum insulation thickness should
be amended in the following formula:
d ¡¦min = (t w -t
a )d
min /60
(5.3.4-2)
where
tw - actual heating media temperature (oC);
ta - air temperature around pipes (o C)
|
| 5.3.5 |
When heating building area is larger than or
equal to 50,000 m2, 10mm more of insulation thickness should be added to
pipes with diameter of 200-300mm on the basis of minimum insulation thickness
in Table 5.3.3.
Minimum insulation thickness of heating pipes
Table 5.3.3
| Insulation materials |
diameter (mm) |
minimum insulation thickness |
| nominal diameter Do |
outer diameter D |
d min (mm) |
rock wool or mineral wool cover
lm =0.0314+0.0002 tm (W/m
¡P K)
t m =70 oC
lm =0.0452 (W/m ¡P K) |
25-32
40-200
250-300 |
32-38
45-219
273-325 |
30
35
45 |
Glass wool cover
lm =0.024+0.00018
tm (W/m ¡P K)
t m =70 o C
lm =0.037(W/m
¡P K) |
25-32
40-200
250-300 |
32-38
45-219
273-325 |
25
30
40 |
Hard polyurethane foam tube (direct burry)
lm =0.024+0.00014
tm (W/m ¡P K)
t m =70 o C
lm =0.03(W/m
¡P K) |
25-32
40-200
250-300 |
32-38
45-219
273-325 |
20
25
35 |
|
| Note: In the table t m
is
mean operating temperature of insulation material, taking mean temperature
of heat media in pipes and air around pipes. |
