CV APS Contact Taiwan Research
Heat Pump
Ecological Implications of Using Urban Rivers to Cool Buildings
River water passing through heat exchangers can be used to heat or cool buildings and hence reduce energy costs. Such technologies have the potential to alter river flow conditions and water temperature but their expected impact on the ecology of urban rivers and riparian ecosystems is unknown. This project will combine field studies (e.g. environmental measurements, community analysis), laboratory experiments (e.g. physiological/behaviour studies) and modelling approaches to investigate the ecological consequences of flow and temperature changes resulting from the use of rivers as a source of cooling.


To investigate the potential for building cooling systems to have ecologically significant impacts on river communities and the riparian ecosystem.

Objective 1:

Investigate the
physical and chemical effects of cooling systems on rivers and riparian zones.

Objective one will be addressed by conducting field surveys. Temporal and spatial variation in environmental conditions (e.g. water temperature, conductivity, velocity, discharge, river widths, river depths, dissolved oxygen, dissolved major ions, pH, turbidity, and air temperature) will be determined for urban river reaches with and without cooling systems.

Objective 2:
Evaluate the effects of cooling systems on periphyton and macroinvertebrate communities.
Objective two will be addressed by regular sampling works. Sampling will take place monthly in sites Macroinvertebrate samples from a hand-net will take from areas with different water velocity and depths, pooled, and immediately preserved in 70% ethanol. Epilithic chlorophyll a will be sampled using a suction device. In the laboratory, macroinvertebrates will be sorted from samples and identified into the lowest taxonomic level, and chlorophyll a samples will filtered onto glass fiber filter, frozen, and analyzed fluorometrically. Adult of aquatic insects will be collected by pyramid emergence traps and stored in 70% ethanol. Data will be used to evaluate the relationship between macroinvertebrate communities (taxon richness, community biomass, and macroinvertebrate densities), the density of chlorophyll a, and the data of adults (taxon richness, adult size, and the timing of emergence) and physical and chemical parameters from objective 1 in urban river reaches with and without cooling systems.

Objective 3:
Evaluate the effect of temperature on the life history of macroinvertebrates.
Objective three will be addressed by two series of laboratory experiments, and a minimum of three residential species will be treated in these series of experiments. The first one is to investigate the effect of water temperature on sex ration, adult size, and the timing of emergence of macroinvertebrates. Five experiments (four treated: 1~4 and one controlled: 5) will be manipulated in laboratory at the same time. Water temperature of the controlled experiment will be simulated by the similar thermal pattern in the sampled sites, and water temperature of experiment 1 to 4 will be increased in specific periods. The second one is to investigate the effect of air temperature on longevity, mortality, and the timing of emergence of macroinvertebrates. This experiment will include two sets. Air temperature of the controlled set will be simulated by the similar temperature in the sampled sites, and air temperature of another set will be increased.

Objective 4:
Predict the scenario of the effect of cooling systems on thermal regime of a river.
Objective four will be addressed by model simulations. Single and multiple thermal effluents will be simulated by Computational Fluid Dynamic software to predict the changes in water temperature in a river.