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Group Members :
1)Lim Yin Ru | 0329931
2) Ngeow Yee Ling | 0329178
3) Teow Kah Yan | 0327201
4) Thasia | 0329051
5) Yap Foong Mei | 0324867
6) Yeo Gin Faye | 0330001
Types of Hot Water Systems
Localised Systems Centralised Systems
Instantaneous Storage Tanks Vented Unvented
Direct Indirect
Electric Immersion Gas Boiler Solar Powered
Localised Hot Water Systems
A system in which water is heated
locally to its needs.
Instantaneous water heaters
• heats flowing water
• water flows through a heating
element
• controlled by a flow switch
• 0.05 litres output flow
Storage tank water heaters
• stores heated water in a tank
• water flows through electric
immersion heater
• controlled by thermostat
• temperature and pressure relief
valves
• 7-130 litres output flow
Centralised Hot Water Systems
A system in which water is heated
and stored centrally within the
building, supplying water through
a system of pipework.
Centralised systems consists of:
- Water heaters
- Hot water storage cylinders
- Cold water storage
cistern/Expansion vessel
Water heating system + Pipework
system
Centralised systems can be
separated into:
Vented systems
Unvented systems
Centralised Hot Water Systems
As water expands when heated, some sort of device must incorporated to
accommodate expansion of the hot water storage cylinder. Expansion vessels are
installed to provide an outlet to allow air to escape.
Vented
• cold water supplied from storage tank
• lower water pressures
Unvented
• cold water supplied directly from
mains
• higher water pressures
Vented Hot Water Heating Systems (Centralised)
Vented hot water cylinder has a cold water is supplied from a storage tank.
• to enable trapped air to escape
• to act as expansion tank - accommodate expansion of hot water
Directly
• uses the principle of convection
• heated directly in the storage vessel
Indirectly
• uses an expansion and feed cistern
• water flowed into boiler through primary flow
and return pipes
• heat energy is transferred indirectly
Types of Hot Water Heaters
Gas Fired
• used in both instantaneous
and storage water heaters
• continuous pilot flame ignites
gas flowing through burner
• heat from flame transferred to
water
Electric Immersion
• most common type of water
heater in Malaysia
• used in both instantaneous
and storage water heaters
• immersion heater placed in
water (transfers heat)
• all electricity converted to heat
Solar
• includes storage tanks and
solar collectors
• solar energy used to heat up
water
• solar energy converted to heat
Tank and Tankless
Comparison Storage Tank Tankless
CONVENIENCE Pre-heat limited water,
refills
and reheat
Provide hot water
sufficiently
EFFICIENCY Operates
continuously, wasted
energy
Heat water on
demand, save energy
COST Less up front but
higher cost to run and
wear out
Slightly more up front
but reduce energy
cost by 60% or more
INSTALALTION &
MAINTENANCE
Most tanks last only
10-12 years. Minerals
build up inside tank
Last up to 20 years
with very little
maintenance
Centralised system and localised systemCentralised system Localised system
require large storage space saves in boiler house space
and fuel store
long length of secondary
pipework will cause large
heat losses
if the unit fails, can carry the
load
one central plant implies
simpler and less maintenance
the number of heater is
added, more gas or electrical
connection
better control in energy
consumption
the risk of fire will increase
reduction in flue construction structural or architectural
aspects may restrict the use
of cheaper fuel
Installation of Hot Water Supply Systems
The main considerations that need to be
taken in to design a hot water supply
system includes:
1. Type of hot water supply system
• Localised or Centralised?
• Direct or Indirect?
2. Supply pipes and water circulation
design
• Location of water heaters
• Piping configurations
• Circulation design
• Zoning
3. Hot Water Heaters
• Electric or Gas?
• Instantaneous or Storage?
Centralised system
Localised system
Zoning
Recirculating
system
Installation of Hot Water Supply Systems
Additional considerations that need to be taken in
to design a hot water supply system includes:
1. Cost and efficiency of the system
• Standby loss
• Tank insulation
• Heat traps
2. Installation and maintenance cost
• Management
• Central hot water generator
3. Storage and distribution temperature
• Stored at approx. 55˚C
• Micro-bacteria (Legionella)
4. Hot water demand requirements
• Water temperature requirements
• Peak periods (Mornings & Evenings)
Insulation
Thermostatic Mixing Valve
Heat traps
TYPE OF PIPEIt’s a galvanized pipe
steel or iron pipe that
has been galvanized
with zinc coating
GALVANIZED PIPE
• Localized hot water system
• The builiding consists of 128 apartments
• Each apartment consist 6 rooms and 1 shared bathroom
• Each bathroom has 2 water closet and 2 shower room
• Each bathroom is fixed with 2 electrical water heater
• Total has 256 hot water heater
• Capacity of water heater is 135 liter
• Heating element voltage is 9kW
• Temperature of hot water stored is 35 degree celcius
HOW IT WORKS ???
1. Cold water is supplied through the blue piping to water heater storage
2. The water heated in a very short time
3. The hot water is then flows out through copper piping to shower head
Case Study 2 ( Overseas )Best Western Plus New Englander Hotel @ Woburn , Massachusetts, USA
Consists of 99
rooms, which
include 2
commercial
washing machines
in it
OLD HOT WATER SUPPLY SYSTEM
Old gas-fired boiler
Storage tank can store up to 1800 liters of hot water
Leakage of water in tank happens
NEW HOT WATER SUPPLY SYSTEM
• Unvented centralized hot water system
• Gas-fired condensing tankless water heaters
• Installed 10 gas-fired condensing water heaters
• The system able to deliver up to 405 liters of hot water per minute
• Temperature of hot water supplied is around 60 degree Celcius
OPERATING SYSTEM
This can
save the
fuel and
electricity
bill
The operating
system of this hot
water supply
system is using
intelligent
cascading
This hotel
has 1
primary
appliance
and 9
secondary
appliances
A signal is sent
to one or more
secondary to
ignite
When the
demand of hot
water is higher
than what primary
appliance can
serve
One of the
appliance serves
as primary
appliance and
attempts to meet
the hot water
demand
Maintenance to maintain the
efficiency of the hot water system
A poorly maintained water heater
system will increase the running
cost and thus, to maintain the
efficiency of the system in long term,
periodic maintenance is necessary. it
will neither consume much time nor
costly unless the system deteriorated
to a point of needing major work or
replacement.
“ Prevention is better than cure “
MaintenanceRegular Inspection
MaintenanceT&P Relief Valve
• checks for cracks, wearing and leaking in piping and ducting
• for solar heating system, check dampers, supporting structures and
flashing and sealant around roof penetrations
• for gas water heater, check if there’s gas leakage
• an equipment that ensures the stability of temperature and pressure of the tank
• a faulty T&P relief valve with high water pressure as a result of runaway overheating will cause explosive steam
Maintenance Water Softener
MaintenanceChlorine
water softener or mild acidic solution can be added every 3-5 years to :
• prevent scaling
• decrease the risk of microbial settlement
• reduce the possibility of water getting infected by microorganism
• to avoid bacterial contamination particularly Legionella
• chlorine inspection should be done anually
• suitable range (0.5mg – 1.0mg)
[ excess may cause chest pain and eye irritation ]
Maintenance Drain
MaintenanceAnti-Freeze
flushing out minerals and other debris that may cause it to malfunction
• prevent scaling
• extend the heater life span
• only occurs during cold climate that falls below 6 degree Celcius
• should be changed every 3-5 years
Future recommendation
Solar water heating system
• commercial building should 100% rely on solar energy as energy source in heating water.
• favorable to be used in Malaysia due to hot climate.
• it absorbs heat from the sun and transfer it to the water
• 2 types of solar water heating system :
a) active solar water heating system
b) passive water heating system
• 2 types of solar thermal panel
a) flat plate collector
b) evacuated tubes collector – capture sunlight better but may
overheat
Cost : flat plate collector –
US $100-500
evacuated tube collector –
US $100-250
Why choose solar thermal??Advantages
• renewable energy
• reduce electricity bill
• recommended for green building
( Green Building Index )
Disadvantages
• initial cost is relatively high
[ running cost is low , cost of conventional fuel is low or near to zero :
depends on the availability of backup units ]
• concern on availability of hot water supply at night
[ backup unit : heat up water when sunlight is insufficient and the water is
not hot enough ]
• less suitable for high rise building
[ panel can be attached to the external wall and facade ]
Additional for future recommendation
Instead of using the traditional electric based heater / boiler , a hybrid electric heat pump water heater should be recommended
• a combination of electric water heated and heat pump
• heat pump function by absorbing heat from
surrounding air and transfer it to the water in the
storage tank
• when demand is high, it will automatically switch to
electric resistance heating
SolutionsAir locks
• water could not flow out
• air release vent should be installed
Imbalance water pressure
• pipe leakage, water hammer & noise pollution may occur
• water pressure regulator should be installed
Pipe leakage
• due to corrosion ( reaction )
• make sure pipe is always filled with hot water
• use stainless steel pipe
Insufficient hot water supply
• use bigger storage tank
• ensure that there is no leakage
Backflow
• definition : unplanned reversal of flow of water
• may occur due to difference in pressure
• can be prevented by providing an air gap
• install backflow prevention devices ( vacuum breaker, double check valve
assembly & reduced pressure backflow assembly