Air Management
Managing circulation of air in a building, including its
temperature, cleanness, and breathability, requires a special system.
Such system usually includes a gravity ventilation system, at
least as a fallback system.
There are two networks of pipes in the building – inflow and
outflow. Water is taken from outflow network, heated or cooled, according the
season, and pumped into the inflow network. When the building has a basement,
it is convenient to use it for design and maintenance of these networks of pips
– pipes going horizontally could be in the basement. Pipes are usually
insulated and buried in walls.
Radiators are plugged between these two networks using short
access pipes. Valves controlling water flow through each radiator are placed in
access pipes.
Such system could be augmented with perpetual supply of fresh
air under pressure slightly higher than air pressure outside the building. This
would support automatic venting of the air from the room. Supplied air could be
heated or cooled according to the season. While this addition is rarely done in
small buildings, it could be done relatively easily.
Advantage of such addition is ability to manage the level of
oxygen in each room separately and to conduct quick venting of existing air in
the room. Usually such venting is done by opening the windows, but, in some
cases, it is not possible.
If we decide to make such addition, than we could improve air
circulation in the room, by placing hot radiators and pipes delivering hot air
on the bottom of the room and cold radiators and pipes delivering cold air on
top of the room.
Due to heat transfer between a room and external environment,
our system has to supply (remove) certain amount of heat to (from) the room.
When temperature of water in the water inflow pipes and temperature of air in
the air inflow pipes is fixed, the amount of heat transferred by the system is
defined by the speed of water flow in the radiators and speed of delivered air
inflow. This speed we control with valves.
This way, we could set temperature in the room by setting two
valves – controlling water inflow and controlling air inflow. This is not much
different from existing water based systems.
However, when we are venting the room aggressively, this raises
temperature in it in the winter, or drops temperature in it in the summer,
dramatically. Sometimes even opening of a door in the room cannot help much.
Hence, we need some additional mechanism to overcome this problem. We need
better control of temperature of delivered in the room air. This could be done,
if in addition to delivery of heated or cooled air, we separately deliver air
at temperature outside of the building – simply filtered external fresh air.
Than we could combine two airstreams delivered in the room in proper
proportions and control temperature of delivered air this way.
Thus, we need a bundle of pipes delivering air in a room, one
pipe in this bundle should carry heated or cooled air, and the other pipe
should always deliver fresh air at external air temperatures. In each room
Each of these pipes in a bundle should have its own valve to allow
separate control of air delivery. In the end of this bundle should be a mixing
cavity with opening into a room, which should have decorative covering the way
it is done in gravity ventilation system.
Since we need to deliver heated air to the bottom of the room
and cooled air to the top of the room, we need two such bundles in a room, one
opening at the top and another at the bottom of the room.
We should handle air delivery the same way we handle water
delivery – using networks of air inflow pipes, to which pipes delivering air
into each room – air delivery access pipes, are connected. Hence, description above
is description of air delivery access pipes.
For removal of air from rooms we need an air removal network of
pipes in the building, with access pipes in each room connected to this
network. Air should be removed from places, where air circulation is weak. In
warm and in cold seasons, these places are different,
hence it should be removed from different places in the room according to the
season. Two air removal access pipes are needed in each room and they should be
switched accordingly.
Because of the pumping of air into rooms, air in the rooms
should be of pressure above atmospheric. This has at least two benefits. First,
this difference of pressure should drive air removal, no pumping is needed.
Second, excess of air pressure in the building should keep external dust away
from it.
There is an additional factor, which has to be taken in
consideration, when one designs such system. It is desirable to have different
pipes carrying hot and cold water and different pipes carrying warm and cool
air. This way, every season, about half of the system of pipes would be idle
and available for examination and repair. Pipes would operate at smaller range
of temperatures and more time would be available for system maintenance and
repair.
Also, it is important to be able to switch the system between
seasons in one place. This could be not trivial, when there are water-based and
air-based subsystems, and when radiators and air delivery openings, serving
during different seasons, are in different places.
Each component of this System has networks of pipes, which serve
as a reservoir of water or air.
In closed circuit components, as water based components, two
such networks are used and heating/cooling devices are plugged between them
using inflow access pipes and outflow access pipes, with one of these access
pipes having a valve. This way, one network becomes inflow network (into
devices) and the other - outflow network (from devices) and a pump perpetually
moves water (or some other substance) from outflow network into inflow network.
In open circuit components, as air based components, one such
network is used and devices are connected just to this network using a pipe,
also with a valve in it. Air (or another substance), is pumped into the network
and released from these devices, or it is removed from the network and devices
absorb the air (or another substance).
Following is description of one such Air Management System,
which could be used in one family houses, as well as in large buildings, like
hospitals, or apartment buildings.
A Water Component of the System
consists of:
·
inflow and outflow networks of pipes filled with
water,
·
radiators with two access pipes connecting it to
inflow and outflow networks,
·
valves, one for a
radiator, in one of the access pipes.
The system has two Water Components,
one for hot water and another for cold water.
The System has two Air Delivery Components,
one for warm air and another for cold air. Each uses two-pipe bundles, where one
pipe in a two-pipe bundle carries fresh air and the other carries either warm
air or cooled air.
The Warm Air Delivery Component
includes:
·
warm air inflow network,
·
fresh air inflow network,
·
two-pipe access bundles providing access to the warm
air inflow network and fresh air inflow network
·
air mixers in these access bundles, where air from
both pipes of two-pipe bundle is mixed,
·
valves in both pipes of each access bundle,
·
opening of air mixers into the room in each access
bundle with covering as in ventilation system
The Cold Air Delivery Component is
similar to Warm Air Delivery Component, only it includes cold air inflow
network instead of warm air network.
The system also has two Air Removal
Components, one used, when warm air is delivered, and another - when cold air
is delivered.
Openings into rooms of these two types
of Air Components are in different places in a room.
The Air Removal Component has an
air outflow network of pipes and access pipes connecting this network to rooms,
where access pipes have opening with covering, as in a ventilation system.
Air should be taken in from a
place, where it is cleanest, for example, from the roof of a building.
It should be filtered and
disinfected, for example, with use of UV light. Health improving fragrant
substance should be added to it after that.
Air in rooms should
have pressure slightly higher than external air pressure. This pressure
difference should move used air out of the room, while new air is pumped in.
Air, which is moving
out – should be first used for heat exchange with air prepared to be pumped
into the rooms. This should be done before incoming air is heated or cooled.
After that, it should be used to
support burning of fuel. Removed air has pressure higher than atmospheric
pressure, hence, it useful during burning of fuel and useful during venting of products
of burning.
Note, that this way, removed air is
disinfected, which is important, when such system is used in a hospital, for
example.
Inflow and outflow networks of
pipes have vertical pipes, usually insulated and placed inside the walls of the
building, and horizontal pipes. The best place for horizontal pipes is in the
basement and in the attic.
Switch between heating and cooling
seasons is done by simultaneous switching of inflow and outflow networks,
because, in this system, different pipes are used in different seasons.
It was a goal of this design to
allow simultaneous switching of Air and Water Components done in one place. This
place should be where all inflow and outflow networks meet – the place, where
heating and cooling is done. This way, all systems could be switched in the
same time.
Gravity ventilation system should
be used during such switch, because air supply and removal systems are
inoperable (for a short period).
After such switch, idle part of the
system should be examined and repaired. It would be a lot of time to do that –
entire season.
During switching of Water
Components, second Component is deployed and first Component is drained of
water first and made ready for inspections and repairs. Air components are
available for inspections and repairs immediately after the switch.
A Water Component includes a set of
radiators used for heating or cooling air in the building, with water of needed
temperature running through them. Speed, with which it runs, and corresponding
heat transfer rate, depend on settings of the valve in
associated access pipe.
Water into radiators comes through an
inflow network of pipes, in which water is pumped, and it flows from the
radiators into an outflow network of pipes. From the outflow network water is
taken, heated or cooled, depending on the type of the Component, and pumped
back into the inflow network. Two access pipes connect a radiator to inflow and
outflow networks:
·
inflow access pipe connects inflow end of the
radiator to the inflow network
·
outflow access
pipe connects outflow end of the radiator to the outflow network.
Taking water from the outflow
network, heating it or cooling, and pumping it into the inflow network is done
in one place in the building. where heating and
cooling is done.
Traditionally, there is only one pair
of networks (inflow and outflow). At the change of the season, the system is
drained and water of different temperature starts circulation through it.
In this design, there are two pairs
of networks and connected radiators, one for warm weather and another for cold
weather – two Water Components.
Radiators from different Water
Components are placed in pairs: one provides heating and another provides
cooling. Heating radiators are placed on the bottom of the wall, often under
windows. Cooling radiators are placed on the top of the wall, often above
windows.
Only one type of radiators (heating
or cooling) in a time is operational, and, hence, only one Water Component is
active in a time.
Pressure of air after a mixer
should be higher than in quarters, then air after mixing flows into a room
naturally.
Pressure of air in the room should
be higher than outside, then air flows out naturally and such elevated air
pressure in the building keeps dust out of it.
There are two outflow Air
Components, one for heating season and another for cooling season. Their
outflow networks are almost identical and go in parallel, but they differ in
their room access pipes. They are switched in the same place and time, where
and when inflow Air Components are switched, i.e. when heating/cooling season
is changed.
Openings of outflow air components
are placed where air circulation in the room is the worst – this placement
provides improvement of air circulation. When inflow Air Component delivers
warm air to the bottom of a wall in a room, the corresponding outflow Air
Component takes air from the bottom of an opposite wall. When inflow Air
Component delivers cold air to the top of a wall in a room, the corresponding
outflow Air Component takes air from the top of an opposite wall.
Combining effects of
radiators and direct delivery of air to achieve desirable comfort requires fine
control of speed of water flow through radiators and speed of flow of air,
pumped into the room through the air mixer. To achieve this, valves have to be
in pipes before water enters radiators and before air enters room.
The work of these valves is to constrict
flow of air and water and this way cause change in speed of heat exchange
between the system and air in the room.
Ability to control these valves
manually should always be present, at least as a fallback system. However, it
is desirable to have some computerized control system to do that. Such system
should have ways to detect air temperature in the room and level of oxygen in
the room. It would need to have some electronic interface, through which
desirable settings could be provided and transmitted.
The control system would attempt to
satisfy a request in bounds of its abilities. This might take some time, while
the Control System tries different settings of valves and checks achieved
results (adaptive control system). In any case, it should end up with parameters
of the environment close to the requested ones.
Alexander Liss 7/16/2020